4 X 4 PLANAR ANTENNA ARRAY FOR ENHANCED GAIN

A PROJECT REPORT
submitted for the fulfillment of the requirements for the award of

BACHELOR OF TECHNOLOGY
in
ELECTRONICS & COMMUNICATION ENGINEERING
By

B. LOHITHA SIRI VARSHINI A. N. V. S. ANIRUDH

203J1A0422 203J1A0402
G. VINEELA A. YASWANTH
203J1A0447 203J1A0401

Under the Esteemed Guidance of

Dr. V. V. S. S. S. Chakravarthy, M. Tech, Ph. D
Assistant Professor

DEPARTMENT OF
ELECTRONICS AND COMMUNICATION
ENGINEERING
RAGHU INSTITUTE OF TECHNOLOGY
(AUTONOMOUS)
(Approved by AICTE, New Delhi & Permanently Affiliated to JNTU-GV, Vizianagaram
Accredited by NAAC with 'A' Grade, Re-Accredited by NBA, Listed u/s 2(f) & 12(B) of UGC
Act 1956)
Dakamarri (V), Bheemili (M), Visakhapatnam-531162, Andhra Pradesh
APRIL 2024

i
 RAGHU INSTITUTE OF TECHNOLOGY
(AUTONOMOUS)
(Approved by AICTE, New Delhi & Permanently Affiliated to JNTU-GV, Vizianagaram
Accredited by NAAC with 'A' Grade, Re-Accredited by NBA, Listed u/s 2(f) & 12(B) of UGC
Act 1956)
Dakamarri (V), Bheemili (M), Visakhapatnam-531162, Andhra Pradesh

DEPARTMENT OF
ELECTRONICS AND COMMUNICATION ENGINEERING

CERTIFICATE
This is to certify that this project report “4 X 4 PLANAR ANTENNA ARRAY
FOR ENHANCED GAIN” is the bonafied work of B. LOHITHA SIRI
VARSHINI (203J1A0422), A. N. V. S. ANIRUDH (203J1A0402), G. VINEELA
(203J1A0447), A. YASWANTH (203J1A0401), who carried out the project work
under my supervision.

HEAD OF THE DEPARTMENT SUPERVISOR

Prof. P. Satish Rama Chowdary, Dr. V.V.S.S.S. Chakravarthy,

M. Tech, Ph. D M.Tech, Ph. D
Vice Principal & HOD Assistant Professor

Submitted for the project viva-voce examination held on______________

INTERNAL EXAMINER EXTERNAL EXAMINER

ii
 ACKNOWLEDGEMENT

Apart from the efforts from us, the success of any project depends largely on the
encouragement and guidelines of many others. We take this opportunity to express our gratitude
to the people who have been instrumental in the successful completion of this project.
We take immense pleasure in thanking Sri. Kalidindi Raghu, Chairman of Raghu
Educational Institutions for having permitted as to carry out this project work.
We are grateful in thanking Sri. Kalidindi Rahul, Vice-Chairman of Raghu
Educational Institutions for having permitted as to carry out this project work.
We would like to extend our thanks to Prof. S. Satyanarayana, Ph. D, Principal, of
Raghu Institute of Technology who had been source of inspiration and for his kind permission
to use the infrastructure in the college and carry out the project work in the college.
We truthfully acknowledge the help and moral support from Prof. P.S.R.Chowdary, PhD,
Dean, Student Affairs of Raghu Institute of Technology for his support and encouragement.
As a token of our feeling, we would like to acknowledge my sincere thanks to Prof. K.P.
Vinay, PhD, Head of the Department of Electronics & Communication Engineering of Raghu
Institute of Technology for allowing us to take upthis project. (Check this sir)
We are extremely thankful to our project supervisor Dr. V. V. S. S. S.
CHAKRAVARTHY, M. Tech, Ph. D Assistant Professor of Electronics & Communication
Engineering of Raghu Institute of Technology, who had been source of inspiration and for
her kindly guidance in the conduct of our project and having permitted us to carry out this project
work.
We wish to express our deep sense of gratitude to teaching staff and non-teaching staff
ofour ECE department for their help and wishes for the successful completion of this project.
Finally, at importantly, we would like to express our heart full thanks to our beloved Parents
for their blessings, our friends/classmates for their help and wishes for the successful
completion of this project.

B. LOHITHA SIRI VARSHINI (203J1A0422)

A. N. V. S. ANIRUDH (203J1A0402)
G. VINEELA (203J1A0447)
A. YASWANTH (203J1A0401)

iii
 DECLARATION

We hereby declare that the project work entitled “4 X 4 PLANAR ANTENNA

ARRAY FOR ENHANCED GAIN” is being submitted to Raghu Institute of Technology,
(Autonomous), permanently affiliated to JNTU-GV, VIZIANAGARAM, in partial
fulfilment for the award of degree in B. Tech in the Department of Electronics and
Communication Engineering. The work was originally designed and executed under the
guidance of our guide Dr. V. V. S. S. S. CHAKRAVARTHY, M. Tech, Ph. D, Professor and
was not a duplication of work done by someone else. We hold the responsibility of the
originality of the work incorporated in this thesis.

B. LOHITHA SIRI VARSHINI (203J1A0422)

A. N. V. S. ANIRUDH (203J1A0402)
G. VINEELA (203J1A0447)
A. YASWANTH (203J1A0401)

iv
 ABSTRACT

This project focuses on the design and optimization of a 4x4 planar antenna array tailored for
operation within the X-band frequency range 7 GHz to 12 GHz. The antenna occupies a space
of 60.5 x 60.5 x 1.6. The antenna configuration, optimized for broadband performance, enables
spatial diversity, offering enhanced reliability and increased data rates. The proposed design
demonstrates its efficacy in the 7 GHz to 12 GHz frequency band, and the gain of the antenna
is 9.7 dB which helps in catering to the evolving needs of wireless communication networks.

The objective is to enhance signal strength, gain, and overall performance for applications in
communication systems, radar systems, and aerospace platforms. RT/Duroid substrate material
was carefully chosen for its favorable dielectric properties, low loss characteristics, and
dimensional stability, aiming to maximize the efficiency and effectiveness of the antenna
design within the X-band frequency range.

The design process involved meticulous consideration of substrate material selection, antenna
configuration, and feed network design. Through iterative simulation and optimization,
parameters were fine-tuned to achieve desired performance metrics such as impedance
matching, radiation pattern, and gain. Experimental validation was conducted to confirm
simulated results, ensuring the accuracy and reliability of the design approach.

Results demonstrate the feasibility of developing a high-performance planar antenna array

optimized for X-band applications. Insights gained pave the way for further research and
development in antenna design, with potential applications in wireless communication, radar
systems, and aerospace technologies. This project contributes to advancements in antenna
engineering, addressing the growing demand for efficient and reliable communication systems
in various industries.

v
 LIST OF CONTENTS
PAGE
TITLE
NUMBER
ABSTRACT -v

LIST OF FIGURES - ix

LIST OF TABLES -x

CHAPTER 1 – INTRODUCTION TO ANTENNA - (01 – 17)

1.1 Overview of Antenna - 01

1.2 Key Antenna Parameters - 02

1.3 Microstrip Patch Antenna - 07

1.4 Antenna Array - 10

1.5 Planar Array Antenna - 12

1.6 Feeding Techniques - 15

1.7 Objectives - 16

1.8 Problem Statement - 17

CHAPTER 2- LITERATURE REVIEW - (18 – 28)

CHAPTER 5 – SIMULATION AND RESULTS - (29 – 40)

3.1 ANSOFT HFSS - 29

3.1.1 Mathematical method used by Ansoft -29

3.1.2 Six general steps for simulation - 30

3.2 HFSS DESKTOP - 31

3.2.1 Menu Bar - 31

3.2.2 Tool Bar - 33

3.2.3 Status Bar - 35

3.2.4 Project Manager - 35

vi
 3.2.5 Properties Window - 37

3.2.6 Progress Window - 38

3.2.7 Message Manager - 38

3.2.8 3D Modeler Window - 39

3.2.9 History Tree - 39

CHAPTER 4 – SIMULATION AND METHODOLOGY - (41 - 46)

4.1 Designing of Micro Strip Antenna - 41

4.1.1 Introduction - 41

4.1.2 Selection of Substrate - 41

4.1.3 Dimensions of Micro Strip Patch - 42

4.1.4 Feeding Implementation - 43

4.1.5 Antenna Modelling - 43

4.2 Designing of Planar Antenna Array - 44

4.2.1 Introduction - 44

4.2.2 Dimensions of Planar Antenna Array - 45

4.2.3 Selection of Substrate - 45

CHAPTER 5 – SIMULATION AND RESULTS - (47–50)

5.1 Single Microstrip Patch Antenna Results - 47

5.1.1 S11 Parameter - 47

5.1.2 Radiation Pattern - 48

5.1.3 Gain Plot - 48

5.2 4x4 Planar Antenna Array Results - 49

5.2.1 S11 Parameter - 49

5.2.2 Radiation Pattern - 50

vii
 5.2.3 Gain - 50

CHAPTER 6 – CONCLUSION AND FUTURE SCOPE - (51–53)

6.1 Conclusion - 51
6.2 Future Scope
-52
REFERENCES
- (54–55)

viii
 LIST OF FIGURES

Figure Page
Figure Details
Number Number
1.1 Variation of Impedance versus Frequency -5

1.2 Basic structure of microstrip patch antenna -8

1.3 Types of patches in microstrip patch antenna -9

1.4 Antenna Array - 10

1.5 Planar Antenna Array - 13

3.1 HFSS Desktop - 32

3.2 Project Manager - 36

3.3 Properties Window - 38

3.4 3-D Modular Window - 39

History Tree
3.5 - 40

4.1 Microstrip Patch Antenna - 41

4.2 Port - 43

4.3 4 X 4 Planar Antenna Array - 44

4.4 Dimensions of 4 x 4 Planar Antenna Array - 46

5.1 The S Parameter Plot - 47

5.2 The Radiation Pattern at 00 - 48

5.3 The Radiation Pattern at 900 - 48

5.4 Gain Plot of Single Patch Antenna - 49

5.5 The S Parameter Plot - 49

5.6 The Radiation Pattern at 00 - 50

5.7 The Radiation Pattern at 900 - 50

5.8 Gain Plot of 4 X 4 Planar Array Antenna - 50

LIST OF TABLES

ix
 Table Page
Table Details
Number Number
1.1 Frequency bands -6

4.1 Dimensions of Micro Strip Patch Antenna - 42

4.2 Dimensions of 4 x 4 Planar Antenna Array - 45

x
 CHAPTER - 1
INTRODUCTION TO ANTENNA
1.1. Overview of Antenna:
The antenna is a metallic structure used for receiving and radiating radiowaves. It is
also a transitional structure between free-space and a guiding structure. As per the reciprocity
principle, the transmission and reception characteristics of an antenna are identical. The same
antenna can be used in two-way communication for both transmission and reception using
suitable receiver protection. The ever-expanding realm of wireless communication relies
heavily on a fundamental component – the antenna.

These specialized devices act as the bridge between the electrical world of signals and
the electromagnetic realm of radio waves, microwaves, and other portions of the
electromagnetic spectrum. Their critical role lies in efficiently transmitting and receiving
electromagnetic waves, enabling seamless data transfer across a vast array of applications, from
mobile communication to satellite systems. This section delves into the essence of antennas,
exploring their core principles, key parameters, and their significance in wireless
communication. Antennas serve as the vital link between the electromagnetic spectrum and our
modern communication systems, acting as conduits for transmitting and receiving
electromagnetic waves. These devices play a crucial role in various fields, including
telecommunications, broadcasting, radar systems, and satellite communications. Antennas
come in a myriad of shapes, sizes, and configurations, each tailored to specific applications
and operating frequencies. From the iconic rooftop TV antenna to sophisticated parabolic
dishes used in deep-space exploration, antennas showcase a diverse range of designs
engineered to optimize signal reception and transmission.

Their functionality extends beyond mere signal propagation; antennas are integral
components in wireless networks, enabling seamless connectivity for smartphones, IoT
devices, and wireless routers. Through the principles of electromagnetism and wave
propagation, antennas convert electrical signals into electromagnetic waves and vice versa,
facilitating the transfer of information over vast distances. The evolution of antenna
technology has been pivotal in shaping the landscape of modern communication, enabling
global connectivity and fostering innovation across industries. Antenna design continues to

RAGHU INSTITUTE OF TECHNOLOGY 1

push the boundaries of efficiency, miniaturization, and adaptability to meet the ever-growing
demands of our interconnected world. From traditional dipole antennas to cutting-edge phased
array systems, the quest for optimal antenna performance drives ongoing research and
development efforts worldwide. As we delve deeper into the realm of wireless communication
and emerging technologies like 5G and Internet of Things (IoT), antennas remain at the
forefront, enabling the seamless exchange of data in an increasingly interconnected world.
Understanding the fundamentals of antenna theory and design is essential for engineers,
researchers, and practitioners in the field of wireless communication, empowering them to
harness the full potential of electromagnetic waves for practical applications. Through this
introduction, we embark on a journey to explore the intricate world of antennas, unravelling
their principles, applications, and impact on modern society. Join us as we delve into the
fascinating realm of antennas, where science, technology, and innovation converge to shape
the future of communication.

1.2. Key Antenna Parameters:

The typical parameters are return loss, antenna resonance, antenna bandwidth, radiation
pattern, voltage standing wave ratio (VSWR), gain, directivity, antenna aperture, antenna
impedances, and beam width.
i. Gain: An antenna's gain quantifies its ability to concentrate its radiated energy in a
particular direction. In simpler terms, it represents how well the antenna amplifies the
signal strength in a specific direction compared to radiating it equally in all directions.
A higher gain antenna focuses its energy more tightly, leading to stronger signals in the
desired direction. The quantity of gain is the efficiency factor times the directivity.

G = KD (1.1)

where, K is an efficiency factor that varies 0 ≤ K ≤ 1.

If the path is not indicated gain can also be represented as

G = 4πU/ Pin (1.2)
where, U is radiation intensity, Pin is the total radiated power
The directivity and gain of an antenna represent the ability to focus its beam in a
particular direction.

RAGHU INSTITUTE OF TECHNOLOGY 2

ii. Directivity: Closely related to gain, directivity is a measure of how well an antenna
concentrates its radiation pattern in a specific direction. It is often expressed in
decibels (dB) and provides a more detailed picture of the antenna's ability to direct its
energy. The directivity is a measure of concentrated radiated power in a particular
direction. It is defined as the ratio of maximum radiation intensity of the antenna to
average radiation intensity in all directions.

D = 4πU/ Prad (1.3)

where, Prad = Total radiated power, U = Radiation intensity.

Directivity is dimensionless and is always ≥1.

iii. Radiation Pattern: Radiation pattern is a three-dimensional graphical representation

of the radiation characteristics of an antenna. But it is measured as a two-dimensional
view of three-dimensional patterns, in vertical or horizontal surfaces called H- and E-
plane radiation patterns. The patterns are measured in polar or rectangular formats. The
pattern depends on the structure of the antenna used. Radiation is referred to as isotropic
radiation, if the antenna is radiating energy equally in all directions. The directive
antennas radiate the power in particular directions.

iv. Impedance: The opposition an antenna presents to the flow of current at a specific
frequency is termed impedance. It is measured in ohms (Ω) and plays a crucial role in
efficient power transfer between the antenna and the connected circuitry. Imagine
impedance as a kind of resistance in the antenna that the electrical signal has to
overcome. For optimal performance, the antenna's impedance needs to be matched to
the impedance of the transmission line or receiver to minimize signal reflection and
maximize power transfer.
v. Bandwidth: The range of frequencies over which the antenna operates effectively is
called its bandwidth. Within this bandwidth, the antenna exhibits consistent
performance in terms of gain, directivity, and radiation pattern. The bandwidth is crucial
for applications where a wide range of frequencies needs to be transmitted or received.
BW = fH – fL (1.4)

where, fH is highest frequency and fL is lowest frequency.

RAGHU INSTITUTE OF TECHNOLOGY 3

 vi. VSWR: Voltage standing wave ratio (VSWR) shows the amount of power reflected
from the feed line due to the mismatch of impedance. For most of the antenna
applications the accepted value of VSWR is 2:1. VSWR of an antenna is
represented as a function of S11
1− |Г|
VSWR = (1.5)
1+|Г|

where Г is a reflection coefficient (S11).

vii. Return Loss: is the measure of power loss due to reflections caused by a mismatch
of antenna impedances. It is given by the ratio of radiated power to the reflected
power.
The return loss is also called the S11 parameter, the reflection coefficient for single
input and a single output. Similarly, S21, S31 and so on represents the multiple inputs
and multiple outputs. The return loss is measured in dB.
S11 = 10 log (pi / po) (1.6)

where, pi and po respectively represents the input and output power.

Return loss can also be expressed as a voltage standing wave ratio (VSWR).
𝑉𝑆𝑊𝑅
S11 = 20 log (1.7)
𝑉𝑆𝑊𝑅−1

viii. Antenna Resonance: The microstrip patch antenna is an equivalent tuned circuit of
inductance and capacitance. At resonant frequency (fr) the inductive reactance is
equal to capacitive reactance. Hence the antenna impedance is purely resistive at
resonance; the resistance is the sum of radiation resistance and radiation loss
resistance.

RAGHU INSTITUTE OF TECHNOLOGY 4

 Fig. 1.1 Variation of Impedance versus Frequency

ix. Beam width: The parameter beam width indicates the pattern of the antenna. Beam
width is defined as an angular representation between two similar sources on opposite
sides of the pattern. Half power beam width (HPBW) is defined by IEEE as "In a
plane containing the direction of beam maximum, the angular separation between
two paths in which radiation intensity is the one-half value of the beam.”.
x. Antenna aperture: The total area in which the power is radiated or received refers
to the aperture of an antenna. For the receiving antenna, it is the area that captures
energy from a passing EM wave. Large aperture antennas have more gain than that
of smaller aperture antennas.
Classification of Antenna:
A classification of antennas can be based on:
• Frequency and size
• Directivity
• Physical construction.
• Application
Frequency and size: Antennas used for HF are different from antennas used for VHF, which
in turn are different from antennas for microwave. The wavelength is different at different
frequencies, so the antennas must be different in size to radiate signals at the correct
wavelength. We are particularly interested in antennas working in the microwave range,
especially in the 2.4 GHz and 5 GHz frequencies.

RAGHU INSTITUTE OF TECHNOLOGY 5

Directivity: Antennas can be omni directional, sectorial or directive. Omni-directional
antennas radiate roughly the same pattern all around the antenna in a complete 360° pattern.
E.g.: Dipole and Ground plane.
Sectorial antennas radiate primarily in a specific area. The beam can be as wide as 180
degrees, or as narrow as 60 degrees. Directional or directive antennas are antennas in which
the beam width is much narrower than in sectorial antennas. They have the highest gain.
Therefore, used for long distance links. Eg: Yagi-Uda, Biquad, horn, helicoidal, patch
antenna, parabolic dish.
Physical construction: Antennas can be constructed in many different ways, ranging from
simple wires, to parabolic dishes, to microstrips.
Application: Access points tend to make point-to-multipoint networks, while remote links
are point-to-point. Each of these suggest different types of antennas for their purpose. Nodes
that are used for multipoint access will likely use omni antennas which radiate equally in all
directions, or sectorial antennas which focus into a small area. Directive antennas are the
primary choice for this application.
BAND FREQUENCY RANGE

HF Band 3 – 30 MHz
VHF Band 30 – 300 MHz
UHF Band 300 – 1000 MHz
L Band 1 – 2 GHz
S Band 2 – 4 GHz
C Band 4 – 8 GHz
X Band 8 – 12 GHz
Ku Band 12 – 18 GHz
K Band 18 – 27 GHz
Ka Band 27 – 40 GHz
V Band 40 – 75 GHz
W Band 75 – 110 GHz
mm Band 110 – 300 GHz

RAGHU INSTITUTE OF TECHNOLOGY 6

 Table 1.1 Frequency bands

1.3. Microstrip Patch Antenna

Microstrip patch antenna (MPA) is one of the most widely used antennas in the
microwave frequency range. The planar microstrip patch antenna is a low profile, low cost,
less weight, easily printable onto circuit board (PCB) and comfortably fabricated patch
antenna, suitable for wireless communication devices. Microstrip patch antennas were first
proposed by G. A. Deschamps in 1953. The first practical antenna was developed in 1970’s by
Robert E. Munson and John Q. Howell. Since then, extensive research is in progress and
enhancement of MPA characteristics as per current demand for wireless and mobile
communication systems. Presently, the wideband performance of communication system
requires a compact wideband antenna to accommodate a large frequency spectrum with
improved gain and bandwidth.

Microstrip patch antennas are constructed using a double-sided metallic coated

substrate. There are various dielectric materials used for design and implementation of MPA
for different applications. The RT-Duriod dielectric material
with a relative dielectric constant (εr = 2.2) is widely used for a higher frequency application
including mobile, wireless, and satellite applications. The dielectric material plays important
role in microstrip patch antenna. Particularly, lower the dielectric constant higher will be the
efficiency and bandwidth of MPA. Similarly, if we use high dielectric constant substrate
material gives narrow bandwidth and less efficiency.
The microstrip patch antenna configuration consists of different shapes ofmetallic
patch coated on the top surface of dielectric substrate. The patch length is typically around
half of the wavelength. The bottom surface of the dielectric substrate is coated with metallic
surface to form a ground plane. The MPAs are excited with different types of feeding
techniques such as microstrip feed, coaxial probe feed, aperture coupled feed and proximity
coupled feed. The microstrip patch antennas are comparatively simple and inexpensive to
manufacture because of its two-dimensional physical geometry. Microstrip patch antenna
with different shapes can be embedded in the outer regions of spacecraft, aircraft and also
used in mobile communication applications.

RAGHU INSTITUTE OF TECHNOLOGY 7

Patch antennas offer several advantages:
1. Low profile: Their planar design makes them ideal for applications where space
constraints are a concern.
2. Ease of fabrication: They can be easily manufactured using printed circuit board
(PCB) technology, leading to cost-effective mass production.
3. Conformability: Their planar nature allows them to be mounted on curved surfaces,
making them suitable for various applications.
4. Integration with circuits: The microstrip technology used in patch antennas enables
them to be seamlessly integrated with electronic circuits on the same substrate.

However, patch antennas also have some limitations:

1. Narrow bandwidth: Their bandwidth is typically smaller compared to other antenna
types.
2. Spurious radiation: Careful design considerations are necessary to minimize
unwanted radiation from undesired modes.

The basic structure of the microstrip patch antenna is as represented in Fig.1.4.

The microstrip patch antenna consists of three important regions
• Patch: The patch is good conducting metallic surface region placed on a dielectric
substrate. It may be etched in any shape like square, rectangular, circular, elliptical,
and some irregular fractal geometries.

Patch
Substrate

Ground plane
Fig. 1.2 Basic structure of microstrip patch antenna

RAGHU INSTITUTE OF TECHNOLOGY 8

 • Substrate: is a dielectric material with suitable dielectric constant “εr”, having loss
tangent “δ” and substrate thickness is “h”. There are various dielectric materials
available and the suitable dielectric material can be chosen depending on the
applications.

• Ground Plane: is a thin flat good conducting metallic region on the other side of the
substrate, which is usually much larger than a patch for better radiations. The
complete ground plane or partial ground plane (printed monopole MPA) can be
employed.
The patch in MPA can be of any shape as depicted in Fig. 1.4. Depending onthe type of
application, suitable patch can be chosen among rectangular, circular, square, dipole,
triangular, elliptical, and circular ring, etc.

Square Rectangle Dipole Hexagon

Triangle Ellipse Circle Ring

Fig. 1.3 Types of patches in microstrip patch antenna

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1.4. Antenna Array
Array antennas represent a remarkable advancement in the realm of communication
technology, revolutionizing the way we transmit and receive signals across vast distances.
Unlike traditional single antennas, array antennas harness the collective power of multiple
antenna elements arranged in a strategic configuration. Think of them as a synchronized team
of antennas working in harmony to amplify signals and improve communication reliability.
This collaborative approach allows array antennas to outperform their single counterparts in
terms of signal strength, coverage, and directional control.
The concept behind array antennas is akin to orchestrating a symphony, where each
antenna element plays a unique role in producing a coherent signal pattern. By carefully
arranging these elements, array antennas can achieve various beamforming techniques,
enabling precise signal focusing and steering. This capability is particularly advantageous in
scenarios where targeted signal transmission or reception is essential, such as in radar
systems, wireless communication networks, and satellite communication.

Fig. 1.4 Array Antenna

Array antennas come in diverse configurations, including linear arrays, planar arrays,
and conformal arrays, each tailored to specific application requirements. Linear arrays, for
instance, consist of antenna elements arranged along a straight line, ideal for applications
requiring narrow beamwidth and high directionality. Planar arrays, on the other hand, feature
antenna elements arranged in two dimensions, offering enhanced flexibility and coverage for
applications like phased array radars and satellite communication systems. Conformal arrays
take on the shape of the surface they are mounted on, making them suitable for applications
where antenna integration with the host structure is paramount, such as in aircraft and ships.

RAGHU INSTITUTE OF TECHNOLOGY 10

 The versatility of array antennas extends beyond traditional communication systems,
finding applications in fields like medical imaging, radio astronomy, and remote sensing. In
medical imaging, array antennas facilitate the creation of high-resolution images by emitting
focused electromagnetic waves and capturing the resulting reflections. Similarly, in radio
astronomy, array antennas enable astronomers to observe celestial objects with unparalleled
precision, unlocking insights into the mysteries of the universe. Additionally, in remote
sensing applications, array antennas play a pivotal role in gathering data for environmental
monitoring, weather forecasting, and earth observation.
As technology continues to evolve, the role of array antennas in shaping the future of
communication and remote sensing becomes increasingly prominent. From enhancing the
performance of wireless networks to advancing the capabilities of space exploration
missions, array antennas continue to push the boundaries of what is possible in the realm of
electromagnetic wave propagation. In this introduction, we embark on a journey to explore
the fascinating world of array antennas, delving into their principles, applications, and impact
on modern society. Join us as we unravel the complexities and uncover the potential of array
antennas in shaping the future of communication technology.
Array antennas come in various configurations, each tailored to specific applications
and requirements. Here are some common types of array antennas:
Linear Arrays: In linear arrays, antenna elements are arranged along a straight line. They
are often used in applications where narrow beamwidth and high directionality are desired,
such as radar systems and point-to-point communication links.

Planar Arrays: Planar arrays consist of antenna elements arranged in a two-dimensional

plane, offering flexibility in beam shaping and coverage. They are commonly used in phased
array radar systems, satellite communication, and wireless communication networks.

Circular Arrays: Circular arrays feature antenna elements arranged in a circular or

cylindrical pattern. They are suitable for applications requiring omnidirectional coverage,
such as in mobile communication systems and satellite tracking.

RAGHU INSTITUTE OF TECHNOLOGY 11

Conformal Arrays: Conformal arrays conform to the shape of the surface they are mounted
on, making them ideal for integration into curved or irregular surfaces, such as aircraft
fuselages, ship hulls, and vehicle bodies.
Planar Phased Arrays: Planar phased arrays consist of multiple planar subarrays, each with
its own phase control. They offer enhanced beam agility and adaptive beamforming
capabilities, making them suitable for advanced radar systems and electronic warfare
applications.

Adaptive Arrays: Adaptive arrays utilize advanced signal processing techniques to

dynamically adjust antenna parameters, such as beam direction and shape, in response to
changing environmental conditions and interference sources. They are used in smart antenna
systems for improving signal reception and mitigating interference in wireless
communication networks.

Patch Arrays: Patch arrays consist of a grid of patch antennas, which are small, low-profile
antennas typically printed on a substrate. They are commonly used in applications requiring
compact size and planar integration, such as in mobile devices, RFID systems, and wireless
sensor networks.

1.5. Planar Array Antenna

Planar array antennas represent a sophisticated class of antenna systems that offer
versatility and adaptability in communication and sensing applications. Unlike traditional
antennas, planar array antennas consist of multiple antenna elements arranged in a two-
dimensional plane, allowing for precise control over beam direction and coverage. These
antennas are widely utilized in radar systems, satellite communication, wireless networks,
and aerospace applications due to their ability to achieve agile beamforming and electronic
steering.
The design of planar array antennas facilitates the creation of complex radiation
patterns, enabling efficient signal transmission and reception over a wide range of
frequencies. They are capable of generating beams with varying characteristics, including
narrow beams for long-range communication and wide beams for broad coverage. Planar
array antennas are particularly suited for phased array systems, where phase shifting

RAGHU INSTITUTE OF TECHNOLOGY 12

techniques are employed to steer the beam electronically without physically moving the
antenna.

Fig. 1.5 Planar Array Antenna

Planar array antennas offer several advantages:

• Directional Control: Planar array antennas offer precise control over beam direction,
allowing for efficient signal transmission and reception in specific directions.
• Beam Agility: They can dynamically adjust beam characteristics, including direction
and shape, using electronic steering techniques, enabling agile beamforming in
response to changing communication needs.
• High Gain: Planar array antennas can achieve high gain, which enhances signal
strength and extends communication range, making them suitable for long-range
communication applications.
• Multiple Beam Generation: They can generate multiple beams simultaneously,
enabling simultaneous communication with multiple users or tracking multiple
targets in radar applications.
• Flat Profile: Their flat and compact profile makes them suitable for integration into
modern communication systems, where space constraints and aerodynamic
considerations are important.

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 • Conformal Integration: Planar array antennas can be integrated into conformal
surfaces, such as aircraft fuselages and vehicle bodies, without compromising
performance, making them suitable for aerospace applications.
However, planar array antennas also have some limitations:
• Complexity: Designing and implementing planar array antennas can be complex and
require sophisticated engineering expertise due to their intricate beamforming
capabilities and electronic control systems.
• Cost: Planar array antennas may be more expensive to manufacture and deploy
compared to traditional antennas, primarily due to the complexity of their design and
the use of advanced materials and technologies.
Planar array antennas find a wide range of applications across various fields due to their
versatile beamforming capabilities and compact design. Some common applications include:
• Radar Systems: Planar array antennas are extensively used in radar systems for target
detection, tracking, and imaging. Their ability to generate multiple beams
simultaneously enables radar systems to scan the surrounding environment efficiently
and detect objects with high accuracy.
• Satellite Communication: In satellite communication systems, planar array antennas
are employed for both ground-based and satellite-based terminals. They facilitate
reliable communication links between satellites and ground stations, enabling the
transmission of voice, data, and video signals over long distances.
• Wireless Communication Networks: Planar array antennas are integral components
of wireless communication networks, including cellular networks, Wi-Fi systems, and
5G networks. They enable the creation of directional communication links, improving
signal strength, coverage, and capacity in densely populated areas.
• Aerospace and Defense: Planar array antennas are used in aerospace and defense
applications, including aircraft, unmanned aerial vehicles (UAVs), and missile
systems. They provide enhanced communication and radar capabilities, supporting
functions such as air traffic control, surveillance, and electronic warfare.
• Radio Astronomy: In radio astronomy, planar array antennas are employed in radio
telescopes for observing celestial objects and studying the universe. Their ability to
capture signals from different directions simultaneously enables astronomers to
conduct detailed observations of galaxies, stars, and other astronomical phenomena.

RAGHU INSTITUTE OF TECHNOLOGY 14

 • Remote Sensing: Planar array antennas are utilized in remote sensing applications,
such as environmental monitoring, weather forecasting, and Earth observation. They
enable the collection of data from satellites and airborne platforms, facilitating
monitoring of the Earth's surface, atmosphere, and oceans.
• Medical Imaging: In medical imaging systems, planar array antennas are used for
techniques such as magnetic resonance imaging (MRI) and microwave imaging. They
help generate focused electromagnetic fields for imaging internal body structures with
high resolution and accuracy.
• Smart Grids: Planar array antennas are employed in smart grid systems for monitoring
and controlling electrical power distribution networks. They enable wireless
communication between smart meters, sensors, and control centers, facilitating
efficient management of electricity distribution.
1.6. Feeding Techniques
Feeding techniques play a crucial role in the performance and functionality of antenna
systems. These techniques involve how electromagnetic energy is delivered to the antenna
elements for transmission or received from them for reception. The choice of feeding
technique depends on factors such as the antenna's design, frequency range, radiation pattern
requirements, and application needs. Various feeding techniques have been developed to
optimize antenna performance and meet specific requirements.
Feeding Methods in Planar Array Antenna:
In planar array antennas, several feeding methods are commonly used to deliver radio
frequency (RF) energy to the antenna elements. These methods ensure efficient coupling of
electromagnetic waves to the radiating elements, enabling the antenna to transmit or receive
signals effectively. Some feeding methods commonly employed in planar array antennas
include:

Microstrip Feeding: Microstrip feeding involves using microstrip transmission lines to

deliver RF energy to patch antenna elements. The microstrip feed lines are typically etched
on a dielectric substrate beneath or adjacent to the radiating elements. This feeding method
is widely used in planar array antennas, such as patch array antennas, due to its simplicity,
low profile, and ease of integration.

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Corporate Feed: Corporate feed involves feeding multiple antenna elements in an array with
a common feed network or distribution system. This method allows for efficient distribution
of RF energy to all elements in the array, enabling precise control of beamforming and
radiation patterns. Corporate feeding is commonly used in planar array antennas, such as
phased array antennas, where individual elements are connected to a central feeding network.
Aperture Coupling: Aperture coupling involves coupling RF energy to or from the antenna
elements through openings or apertures in a conducting surface. In planar array antennas,
aperture coupling may be used to feed elements in a reflector array or slot array configuration.
This feeding method allows for efficient transmission and reception of electromagnetic waves
while minimizing interference and losses.

Proximity Coupling: Proximity coupling involves coupling RF energy to or from the

antenna elements using nearby electromagnetic fields generated by a feeding structure. In
planar array antennas, proximity coupling may be achieved by positioning a feeding element
close to the radiating elements without direct physical contact. This feeding method enables
compact and low-profile antenna designs while ensuring efficient energy transfer.

Balanced Feeding: Balanced feeding involves feeding antenna elements with balanced
transmission lines, such as twin-lead or twisted-pair cables. This method helps minimize
common-mode radiation and interference, making it suitable for planar array antennas
operating in environments with high electromagnetic interference (EMI) levels.

1.7. Objectives
These are the main project objectives which concisely outline our project’s goals and
intentions.
➢ Develop a 4x4 planar antenna array to achieve substantial gains in signal strength and
overall antenna performance.
➢ Explore and analyze the performance of the antenna array across different frequency
bands, ensuring versatility and applicability in various communication systems.
➢ Find the best way to set up the antenna array elements so that the signal strength is as
high as possible.

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 ➢ Optimize the array configuration of our antenna to maximize enhance overall signal
strength which will lead to good communications.
Conduct a performance evaluation and compare our 4X4 Planar Antenna Array results to
existing technologies for efficiency and effectiveness.

1.8. Problem Statement

In today's rapidly evolving communication landscape, the demand for high-
performance antenna systems continues to grow. However, traditional antennas often face
limitations in terms of signal strength, coverage, and adaptability to different communication
standards. This poses a significant challenge for designers and engineers seeking to develop
antennas that meet the diverse needs of modern communication systems.
Our project aims to address this challenge by designing and optimizing a 4x4 planar
antenna array system capable of delivering substantial gains in signal strength and overall
performance across various frequency bands. By exploring different configurations and
optimization techniques, we seek to enhance the antenna's versatility and applicability in
diverse communication environments. Through rigorous experimentation and analysis, we
aim to develop a robust antenna solution that outperforms existing technologies and meets
the growing demands of today's communication networks.

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 Chapter-2
LITERATURE REVIEW
We explored existing research and studies related to planar array antennas which helped us in
building a good foundation for our project, providing insights into the current state-of-the-art
in planar antenna technology. By reviewing relevant literature, we aim to identify key trends,
challenges, and advancements in the field, as well as gaps in knowledge that our project seeks
to address. Through this exploration, we hope to build upon existing research and contribute
new insights to the body of knowledge surrounding planar array antennas.

4x4 Circularly Polarized Antenna Array for Ambient RF Energy Harvesting [1]

This paper proposes a 4x4 circularly polarized (CP) antenna array for ambient RF energy
harvesting. It utilizes a sequentially rotated feeding network to achieve CP in a 2x2 array, which
is then repeated to form the 4x4 array. The proposed design offers wide axial ratio bandwidth
(1.53 GHz) and is suitable for harvesting RF energy from various directions due to its radiation
pattern.

Microstrip Array Antenna Design for C-Band Satellite Applications [2]

The paper proposes a 4x4 circularly polarized (CP) antenna array for ambient RF energy
harvesting. It utilizes a sequentially rotated feeding network to achieve CP in 2x2 sub-arrays
and employs microstrip-to-CPW transitions for connection. The design offers wide axial ratio
bandwidth (1.53 GHz) and harvests energy from various directions due to its pattern with
multiple lobes. While the gain is low (2.22 dBi), it is suitable for the target application due to
the uncertain source direction. Existing works focus on single frequencies or lack CP for
ambient energy harvesting.

Research on Planar Antenna Arrays [3]

This paper discusses research on planar antenna arrays for satellite communication. The authors
propose several design techniques to improve performance, including reducing cross
polarization and increasing gain and efficiency. They discuss single-band and dual-band
antenna arrays with various polarization techniques. Calibration methods for large arrays are
also presented.

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Planar Array Antenna for Ultra Wide band Microwave Imaging System [4]

This paper proposes a planar antenna array design for an ultra-wideband (UWB) microwave
imaging system for breast cancer detection. The array uses corrugated tapered slot antennas to
achieve wide bandwidth and operates in a coupling medium to improve matching with the
imaged object. The design achieves good return loss and low mutual coupling between
elements through simulations.

Design of a 4x4 Square Microstrip Planar Array [5]

The paper describes the design of a 4x4 microstrip patch antenna array for wind profiling
radars. The array is designed to operate at 1.28 GHz and achieve a gain of 32 dBi. A coaxial
feed is used to connect the inner conductor to the radiating patch. The design process is carried
out using IE3D simulation software. A single element antenna is first designed and optimized,
and then a 2x2 and a 4x4 array are designed using the single element as the building block. The
measured results show good agreement with the simulated results.

Characterization of 4x4 Planar Antenna Arrays for the Frequencies 77 GHz and 94 GHz
Using an Antenna Scanning System [6]

The paper presents a design and characterization of 4x4 planar phased-array patch antennas
operating at 77 GHz and 94 GHz. The antennas are designed for millimetre wave
communication applications. A high-precision antenna scanning system was developed to
measure the radiation patterns of the antennas. The measured results show good agreement
with simulations.

Dual-Polarized Circular Array Antenna for PCL Systems [7]

This paper proposes a new circular array antenna design that achieves dual polarization in two
separate frequency bands without using a complex crossed structure. The antenna offers
compactness and weight reduction. Simulations show the design works as intended with
vertical polarization in VHF_I and horizontal polarization in VHF_II. The study also explores
digital beamforming algorithms to improve the array's performance.

RAGHU INSTITUTE OF TECHNOLOGY 19

X Band 4 X 4 butler matrix for microstrip patch antenna array [8]
This paper designs a 4x4 Butler matrix at X-band for a satellite application. The Butler matrix
feeds a circularly polarized patch antenna array to generate four steerable beams. The desired
beam directions are achieved with acceptable phase errors and coupling levels. The antenna
array offers wide coverage with main lobes at +/ - 15 degrees and +/ - 40 degrees. Existing
works focus on switched beam antennas or lack design details for Butler matrices.

4x4 Circularly Polarized Antenna Array for Ambient RF Energy Harvesting [9]

This paper proposes a 4x4 circularly polarized (CP) antenna array for ambient RF energy
harvesting. It utilizes a sequentially rotated feeding network to achieve CP in a 2x2 array, which
is then repeated to form the 4x4 array. The proposed design offers wide axial ratio bandwidth
(1.53 GHz) and is suitable for harvesting RF energy from various directions due to its radiation
pattern.

Microstrip Array Antenna Design for C-Band Satellite Applications [10]

The paper proposes a 4x4 circularly polarized (CP) antenna array for ambient RF energy
harvesting. It utilizes a sequentially rotated feeding network to achieve CP in 2x2 sub-arrays
and employs microstrip-to-CPW transitions for connection. The design offers wide axial ratio
bandwidth (1.53 GHz) and harvests energy from various directions due to its pattern with
multiple lobes. While the gain is low (2.22 dBi), it is suitable for the target application due to
the uncertain source direction. Existing works focus on single frequencies or lack CP for
ambient energy harvesting.

High gain and Wide bandwidth Filtering Planar Antenna Arrays Based Solely on
Resonators [11]

This paper proposes a new method for designing wide-bandwidth planar antenna arrays using
resonator coupling theory. The arrays are designed to integrate filtering functionality,
eliminating the need for external bandpass filters. The design approach is validated by
constructing two prototype filtering antenna arrays, one with a 7th-order and 39 resonators, and
another with a 4th-order and 25 resonators. Both arrays achieve good agreement between
simulated and measured results.

RAGHU INSTITUTE OF TECHNOLOGY 20

Design and Analysis of a Non-Uniform Planar Antenna Array [12]

This paper proposes a new design for a non-uniform planar antenna array to address mutual
coupling issues in MIMO systems. The key aspects are, Rows are shifted with an angle change
to reduce mutual coupling, achieves high directivity, radiation efficiency, and gain with reduced
sidelobe level, Ideal for MIMO and other applications due to low isolation between elements.
The proposed design offers a potential solution for high data rate wireless communication by
mitigating mutual coupling and enhancing array performance.

A Dual-Polarized Planar-Array Antenna for X-Band and X-Band Airborne Application

[13]

This article presents a new dual-band dual-polarized array antenna for airborne applications.
The antenna is designed to operate at X-Band (3 GHz) and X-band (10 GHz). It is made up of
two separate antenna arrays, one for each band, printed on different layers of a substrate. The
X-Band antenna array is on the top layer, and the X-band antenna array is on the bottom layer.
A foam layer is placed between the two antenna arrays to isolate them from each other.

High Gain Series fed Planar Microstrip Antenna Array using printed L –probe feed [14]

This paper proposes a series-fed microstrip antenna array design using a printed L-probe feed
technique. The L-probe feed offers additional design parameters for impedance tuning,
achieving a good balance between bandwidth and gain. A 5x1 linear array achieves 15.5 dBi
gain and 5.75-6.23 GHz bandwidth. A 5x5 planar array design achieves 18.6 dBi gain and 5.5-
6.42 GHz bandwidth. The proposed design offers advantages in reduced feed network
complexity compared to conventional microstrip antenna arrays.

Millimetre-Wave Planar Array Antennas for Electronic Beam-Scanning Systems [15]

The paper discusses the development of two types of millimetre-wave planar array antennas
for electronic beam-scanning systems. It explores the design and performance of microstrip
and waveguide antennas arranged in sub-arrays for high-gain beamforming. The antennas are
optimized for automotive radar systems, aiming to achieve high angular resolution and wide
coverage. Experimental results demonstrate the effectiveness of both antenna types, with the
microstrip comb-line antenna achieving 20.3 dBi gain and 55% efficiency, while the narrow-
wall slotted waveguide antenna achieves 21.3 dBi gain and 52% efficiency at 77 GHz.

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Design of a Spherical Array by Orthogonal Projection of a Planar Microstrip Antenna
Array [16]

This paper designs a spherical conformal microstrip antenna array by projecting a planar
microstrip array. The planar array is fed by a corporate feed network and achieves good
performance. Projecting the planar array onto a sphere creates a conformal antenna. The
simulation results show the conformal antenna has comparable performance to the planar array.

Planar Ka-Band Antenna Array Based on Slotted Waveguide Structures [17]

This paper proposes a design for a circularly polarized planar antenna array using slotted
waveguides. The design offers low mechanical height and avoids complex feeding networks
compared to microstrip designs. The simulations show good agreement with the fabricated
linear array antenna. A planar array antenna is achievable based on this approach. Future work
will focus on mitigating limitations in scanning angle and polarization purity.

Circularly Polarized Patch Antenna Array for 5G Applications [18]

The paper investigates designing linear and planar microstrip patch antenna arrays for 5G
applications. Rogers RT/Duroid 5880 substrate is used. The arrays achieve multiband
resonance frequencies between 24 GHz and 80 GHz. The linear array has higher gain (up to
14.22 dB) while the planar array has wider bandwidth and better return loss.

W-Band Large-Scale High-Gain Planar Integrated Antenna Array [19]

The paper proposes a design for UWB pulse antennas and antenna arrays. It analyses UWB
signals, antenna designs, radio links, and MIMO UWB systems. The designed antennas are
applicable in modern radiocommunication systems. Their design offers advantages such as
compactness, low-cost fabrication, and high-gain over a wide bandwidth. They achieve this by
using a two-layer structure with SIW feeding network on the bottom layer and radiating patches
on the top layer.

Ultrawideband Planar Antennas and Antenna Arrays [20]

This paper proposes a complex design approach for UWB pulse antennas and antenna arrays.
It analyses UWB signals, single/two-element antenna designs, radio links, and MIMO UWB
systems. Designed antennas may be used in modern radiocommunication systems.

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Sequentially Rotated Broadband Circularly Polarized Stacked Patch Array Antenna [21]

This paper describes a design of a sequentially rotated broadband circularly polarized stacked
patch array antenna for data and voice communication. The authors achieved wide bandwidth
by using stacked patches and sequential rotation technique. A corporate feed network is used
to excite the patches with equal amplitude and 90° phase difference. Measured results show
good agreement with simulated results. The antenna offers wide bandwidth, low axial ratio,
and good gain.

Low-Profile Scalable Phased Array Antenna at Ku-Band for Mobile Satellite

Communications [22]

The document describes a design of an 8x8 phased array antenna tile for Ku-band mobile
satellite communications. The array features low-profile, high-gain, and wide-angle scanning
properties. Prior research has investigated single-feed dual-band antennas and dual-band
antenna arrays for various applications. This design uses a multilayer patch structure to achieve
wideband performance. The radiating element consists of a parasitic patch, a radiating patch,
feeding lines, and ground planes. Simulations show that the array meets the requirements for
gain, scan range, and polarization matching.

Design of a Dual-Band High Gain Antenna Array for WLAN and WiMAX Base Station
[23]

The paper describes a dual-band high gain antenna array for WLAN and WiMAX base stations.
It consists of folded dipole antennas and a microstrip feedline network. The array achieves dual
10-dB RL bands covering WLAN and WiMAX bands. It has a high gain in +z direction, low
cross-polarization, and a high front-to-back ratio. These properties make it suitable for WLAN
and WiMAX applications. Prior work has investigated single-feed dual-band antennas and
dual-band antenna arrays for various applications.

A Novel Near-Field Robotic Scanner for Surface, RF and Thermal Characterization of

Millimeter-Wave Active Phased Array Antenna [24]

This paper describes a novel robotic scanner for characterizing active phased array antennas.
It measures surface features, electromagnetic properties, and thermal response under controlled
temperatures. Robotic arms are increasingly used for antenna measurements due to their

RAGHU INSTITUTE OF TECHNOLOGY 23

versatility and ability to perform complex scans. The authors emphasize the importance of
accurate temperature control for characterizing phased arrays. Previous research has shown
that temperature gradients can significantly impact the performance of these antennas. This
scanner integrates a multi-sensor suite including an RF probe, high-definition camera, and
thermal camera. Machine vision is used to measure the locations and orientations of antenna
elements. The scanner is expected to be a valuable tool for developing and evaluating
calibration techniques for phased array antennas.

4x4 Rectangular Patch Array Antenna for Bore Sight Application of Conical Scan X-
Band Tracking Radar [25]

This paper proposes a design for a 4x4 rectangular patch array antenna operating at X-Band
(2.73 GHz) for boresight application in a tracking radar. Corporate feed network is used to
achieve uniform excitation for high gain and moderate side lobes. Inset-fed patches with
quarter wave impedance transformers are used on a substrate with εr=2.2 and h=3.175 mm.
The simulated results show an impedance bandwidth of 250 MHz, a gain of 18.4 dB, and
sidelobe levels below -6.5 dB. CST Microwave Studio 2006 was used for simulations.

A Flip-Chip Packaged Design of Planar Antenna Array Based on Dual-feed Network for
77-GHz Automotive Radar [26]

This paper proposes a 77 GHz flip-chip packaged antenna array design for automotive radar.
The design utilizes a dual-feed network to combine power from multiple PAs on-antenna,
eliminating the need for lossy power combiners or bulky antenna arrays. A series-fed linear
antenna array is used as an example. The dual-feed network is implemented using a
combination of SIW and microstrip lines with a broadband transition for minimal insertion
loss. Simulations show the design achieves good reflection coefficients, desired radiation
patterns, and potential for use in automotive radar systems.

Millimeter-Wave Planar Antenna Array with Circular Polarization [27]

The paper proposes a new design for millimeter-wave antenna arrays with circular polarization.
The design uses a printed planar antenna with two open rings on opposite sides of the substrate.
The antenna elements are arranged in an 8x8 array and fed by a synphase network. The
fabricated antenna achieves a gain of 20 dBi and a bandwidth of 25% around 60 GHz. It is
simple to fabricate and shows good reproducibility.

RAGHU INSTITUTE OF TECHNOLOGY 24

Offset Reflector Antenna Performance Fed by 2×2 Microstrip Antenna Array using GO
Technique [28]

This paper investigates a 2x2 microstrip antenna array feeding an offset reflector antenna at 20
GHz. The authors use geometrical optics (GO) to analyse the effect of separation distance
between the array elements on cross-polarization and sidelobe levels. They find a separation of
0.8 wavelengths offers the best trade-off. HFSS simulations are used to validate the GO results
for the secondary radiation pattern. Future work will explore more complex array
configurations.

Design of Planar 8-by-16 Butler Matrix for 16-Element Switch-Beam Antenna Array [29]

This paper proposes a new design for a 16-element switched-beam antenna array operating at
9.4 GHz. The key innovation is an 8x16 Butler matrix implemented using microstrip
technology. This matrix combines a conventional 8x8 Butler matrix with 180-degree hybrid
couplers to expand the number of output ports to 16. This allows the antenna array to generate
16 switchable beams instead of the usual 8.

Synthesizing Shaped Power Patterns for Linear and Planar Antenna Arrays Including
Mutual Coupling by Refined Joint Rotation/Phase Optimization [30]

This article proposes a method using joint rotation/phase optimization to achieve shaped
patterns without requiring multiple unequal power dividers, simplifying the feeding network.
Antenna arrays with desired power pattern shapes are crucial in various applications like
satellite communication and sensing systems. Existing methods for shaped pattern synthesis
often involve optimizing both excitation amplitudes and phases, leading to complicated feeding
networks.

Millimeter-Wave Wideband High-Efficiency Circularly Polarized Planar Array Antenna

[31]

This paper proposes a new design for a CP antenna array that offers wide axial ratio (AR)
bandwidth and high efficiency at Ka-band frequencies. Circularly polarized (CP) antennas are
desirable due to their ability to mitigate multipath interference and ease of polarization
matching.

RAGHU INSTITUTE OF TECHNOLOGY 25

2 × 2 Slot Dipole Array Antenna with CPW for 2.4GHz Band [32]

The paper proposes a 2x2 slot dipole array antenna for 2.4 GHz band applications. It utilizes a
coplanar waveguide (CPW) feed and a reflector to achieve high gain and sharp beam. The
design offers easy fabrication on a PCB and achieves 9.39 dBi gain with good bandwidth and
front-to-back ratio. Simulations and measurements validate the antenna performance. Existing
research on patch antennas and slot antennas for high gain at 2.4 GHz is referenced.

The impact of different power dividers used in a non-uniform planar antenna array [33]

The paper investigates the impact of power divider isolation on a circularly polarized antenna
array. Wilkinson power dividers with resistors provide isolation between output ports, leading
to better performance and wider bandwidths for the array compared to using T-junctions
(without resistors).

Planar switchable 3D-coverage phased array antenna for 28 GHz mobile terminal
applications [34]

The paper proposes a planar switchable 3D-coverage phased array antenna for 28 GHz mobile
terminal applications. The design utilizes chassis surface waves to achieve 3D coverage with
three subarrays. The user effects on the proposed antenna are studied in talk mode and data
mode.

Microstrip Planar Array Antenna at Millimeter Wave Frequencies Using a Series-Parallel

Feed Network [35]

This paper proposes a novel design for a microstrip planar array antenna operating at Ka-band
frequencies (26.5 GHz to 29.5 GHz) for Local Multipoint Communication Systems (LMCS)
applications. This paper presents a promising design approach for millimeter-wave microstrip
antenna arrays. The series-parallel feed network offers potential benefits, but further research
is needed to compare its performance with existing solutions and address the gain discrepancy
between simulations and measurements.

RAGHU INSTITUTE OF TECHNOLOGY 26

A Planar Microstrip RF energy harvester 3D cube antenna for multiple frequencies
Reception [36]

The proposed design offers a multi-frequency approach to RF energy harvesting, potentially

increasing the amount of energy captured from ambient sources. Combining different patch
array types within the 3D structure provides flexibility for targeting specific frequency bands.

A 60 GHz 8x8 Planar Array Antenna with Corporate Feed Network using Meandered
Probe Fed Patch in LTCC Technology [37]

This paper presents a compelling design for a high-gain antenna array at 60 GHz using LTCC
technology. The design leverages Low-Temperature Co-fired Ceramic (LTCC) technology and
the use of meandered probe fed patches and a corporate feed network contributes to achieving
a wide bandwidth and efficient power distribution. The simulations indicate promising
performance for 5G applications.

Wideband Circularly Polarized 2×2 Array Antenna Fed by 3D Meandering Probes [38]

This paper proposes a design for a wideband circularly polarized (CP) antenna array using a
novel 3D meandering probe (3D M-Probe) feeding technique. This work presents a novel
feeding technique (3D M-Probe) for wideband CP antenna arrays. The design offers advantages
over previous approaches by achieving good impedance and AR bandwidth while maintaining
a compact size. This makes it suitable for applications requiring high gain and wideband
performance, such as satellite communication.

Design of All-Metal Vivaldi Phased Array Antenna [39]

This research tackles limitations of circuit board Vivaldi antennas for airplanes. These antennas
are ideal for radar due to their wide frequency range, but suffer from signal loss, complex
installation, and weak structure. The study proposes a new all-metal Vivaldi design that boasts
lower signal loss, simpler construction, increased strength, and lighter weight - perfect for
aircrafts. Simulations and tests confirm the antenna's wide operational range (6-12 GHz) and
ability to steer radio waves. This metal design offers advantages over traditional antennas,
making it suitable for applications requiring wide bandwidth and durability.

RAGHU INSTITUTE OF TECHNOLOGY 27

Performance of a Microstrip Planar Array Antenna at Millimeter Wave Frequencies
Using a Series-Parallel Feed Network [40]

This study tackles signal loss in millimeter-wave antenna arrays for communication systems.
It proposes a new design with a series-parallel feed network to reduce losses and improve
performance. Simulations show promising results with high gain and wide bandwidth. A
prototype array was built and tested, confirming the radiation pattern but showing lower gain
than simulations. Future work will compare this design to others and address the
gain difference.

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 CHAPTER-3

INTRODUCTION TO HFSS SOFTWARE

3.1 ANSOFT HFSS

HFSS is a commercial finite element method solver for electromagnetic structures from
Ansys. It is one of several commercial tools used for antenna design, and the design of complex
RF electronic circuit elements including filters and transmission lines. HFSS Ansoft HFSS
software is used to design an antenna in a 3D geometry. HFSS is abbreviated as High-
Frequency Structure Simulator. The basics of HFSS are studied below.is a high-frequency
structure simulator it is a high-performance full-wave electromagnetic field simulator 3D
volumetric passive device modelling that takes advantage of the familiar Microsoft Windows
graphical user interface. It integrates simulation, visualization, solid modelling, and automation
in easy to learn environment.

ANSYS HFSS software is the industry standard for simulating high-frequency

electromagnetic fields. Its gold-standard accuracy, advanced solvers, and high- performance
computing technologies make it an essential tool for engineers tasked with executing accurate
and rapid design in high-frequency and high- speed electronic devices and platforms. HFSS
offers state-of-the-art solver technologies based on finite elements, integral equations, and
asymptotic and advanced hybrid methods to solve a wide range of microwave, RF, and high-
speed digital applications. HFSS delivers 3-D full-wave accuracy for components to enable RF
and high-speed design. By leveraging advanced electromagnetic field simulators dynamically
linked to powerful harmonic balance and transient circuit simulation, HFSS breaks the cycle
of repeated design iterations and lengthy physical prototyping. With HFSS, engineering teams
consistently achieve a best-in-class design in a broad range of applications including antennas,
phased arrays, passive RF/mW components, high-speed interconnects, connectors, IC
packaging, and PCBs. When combined with Ansys HPC technologies, like domain
decomposition or distributed frequencies, HFSS can simulate at a speed and scale never before.
Thought possible, further allowing you to more fully explore and optimize your device's
performance. With HFSS you know your designs will deliver on their product promise.

RAGHU INSTITUTE OF TECHNOLOGY 29

3.1.1 Mathematical method used by Ansoft:

HFSS uses a numerical technique called the finite element method (FEM). This is a procedure
where a structure is subdivided into many smaller subsections called finite elements. The finite
elements used by HFSS are tetrahedral, and the entire collection of tetrahedral is called Mesh.
A solution is found for the fields within the finite elements, and these fields are interrelated so
that Maxwell's equations are satisfied across inter-element boundaries. Yielding a field section
for the entire original structure, once the field solution has been found, the generalized S-
matrix is determined.

3.1.2 Six general steps for simulation:

There are six general steps to creating and solving a proper HFSS simulation, they are:

1. Create model/geometry
2. Assign boundaries
3. Assign excitations
4. Set up solution
5. Solve
6. Post-process the results
Step 1: The initial task in creating an HFSS model consists of the creation of ten physical model
that a user wishes to analyse. This model creation can be done in HFSS using a 3D modeler.
The 3D modeler is fully and will allow a user to create a structure that is variable concerning
geometric dimensions and material properties.

Step 2: The assignment of "boundaries" generally is done next. Boundaries are applied to
specifically created 2D (sheet) objects or specific surfaces of 3D Objects.

Step 3: After the boundaries have been assigned, the excitations (or port) should be applied.
As with boundaries, the excitations have a direct impact on the quality of the results that HFSS
will yield for a given model. While the proper creation and use of excitations are important to
obtaining the most accurate HFSS results, there are several convenient rules of thumb that user
can follow.

Step 4: Once boundaries and excitations have been created, the next step is to create a solution
setup. During this setup, a user will select a solution frequency, the desired convergence

RAGHU INSTITUTE OF TECHNOLOGY 30

criteria, the maximum number of adaptive steps to perform, a frequency band over which
solutions are desired, and what particular solution and frequency sweep methodology to use.

Step 5: When the initial four steps have been completed by an HFSS user, the model is now
ready to be analysed. The time required for an analysis is highly dependent upon the model
geometry, the solution frequency, and available computer resources. A solution can be
beneficial to use the remote solve capability of HFSS to send a particular simulation run to
another computer that is local to the user's site. This will free up the user's PC so it can be used
to perform other work.

Step 6: Once the solution has finished, a user can post-process the results. Post-processing of
results can be as simple as examining the S-parameters of the device modelled or plotting the
fields in and around the structure. Users can also examine the far fields created by an antenna.
In essence, any field quantity or S, Y, and Z parameters can be plotted in the post-processor.
Additionally, if a parameterized model has been analysed, families of curves can be created.

3.2 HFSS DESKTOP:

The HFSS desktop consists of several windows, a menu bar, toolbars, a project manager, a
property window, a message manager, a progress window, a 3D modeler window, status bar.

3.2.1 Menu Bar:

The Menu bar enables you to perform all HFSS tasks, such as managing projects, customizing
the desktop, drawing objects, and setting and modifying all project parameters. HFSS contains
the following menus, which appear at the top of the desktop

File menu: Use the file menu commands to manage HFSS project files and printing options

Edit menu: Use the Edit menu commands to modify the objects in the active model and undo
and redo actions.

View menu: Use the view menu commands to display or hide desktop components and model
objects, modify 3D modeler window visual settings, and modify the model view.

Project menu: Use the project menu commands to add an HFSS design to the active project
view, define data sets and define the project variables.

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Draw menu: Use the Draw menu commands to draw one, two-, or three- dimensional Objects,
and sweep one- and two-dimensional objects.

3D Modeler menu: Use the 3D Modeler menu commands to import, export, and copy Ansoft
2D modeler files and 3D modeler files; assign materials to objects; manage the 3D Modeler
window's grid settings; define a list of objects; control surface settings; perform Boolean
operations on objects and set the units for the active design.

HFSS Menu: Use the HFSS menu to set up and manage all the parameters for the active
Project. Most of these project properties also appear in the project tree.

Tools Menu: Use the Tools menu to modify the active project's material library, arrange the
material libraries, run and record scripts, update project definitions from libraries, customize
the desktop toolbars, and modify many of the software's default settings.

Window menu: Use the window menu commands to rearrange the 3D model window and
toolbar icons.

Help menu: Use the window menu commands to access the online help system and view the
current HFSS version information

Figure 3.1 HFSS Desktop

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3.2.2 Tool Bar:

The toolbar buttons and shortcut pull-down lists act as shortcuts for executing various
commands.

Drawing objects: We can draw one, two, or three-dimensional objects using the Draw
commands. You can alter objects Individually or together to create the geometry of your
structure. In the toots>3D modeler Options, drawing tab, you can set a default to either draw
objects directly with the mouse or by invoking a properties dialog in which you can enter the
values for the objects directly with the mouse or by invoking a properties dialog in which you
can enter the values for the object dimensions. The dialog mode drawing feature works with
the equation- based line and all 3-dimensional objects.

One dimensional: Object sine HFSS including straight-line arc line spelling segments or a
combination of these called polylines. One-dimensional objects are open objects; their
boundaries do not enclose a region unless you connect their endpoints. They have length, but
no surface volume; generally, they are used as temporary objects from which to create a 2D
object.

Two dimensional: Objects in HFSS include objects such as arcs, rectangles, ellipse, circles,
and regular polygons. Two-dimensional objects are closed sheet object boundaries enclosed by
a region. You can create a 2D sheet object by covering by enclosed region. By default, the
history tree organizes sheet objects around their boundary assignments. To change this, select
the sheet icons and click to display the

group sheets by an assignment check box.

Three-dimensional: Objects in HFSS include objects such as boxes, cylinders, regular

polyhedrons, cones, spheres, and helixes. These objects have boundaries that enclosed a region
with value. You can create a 3D object by calculating a 2D object along a plane or by using the
approximate draw commands. By default, the history tree group's 3D objects by material. To
change this, select the object icons, and right-click the displaying the group object by a material
check box.

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Drawing a straight-line segment: To create an object with one or more straight line segments,
use the Draw>Line command.

Drawing a three-point arc line: In HFSS, a three-point arc line segment is an arced line
defined by three points on its curve. Use the Draw>Arc>3-points command to create a polyline
object with one or more arc line segments.

Drawing a center-point arc line: In HFSS, a center-point arc line segment is an arced line
defined by a center point, start point, and angle Use the Draw>Arc>Centre Point command to
create a polyline object with one or more center-point arc line segments.

Drawing a polyline: A polyline is a single object that includes any combination of a straight
line, or spline segments. The endpoint of one segment is the start point for the next segment.
Use the shortcut menu's Set Edge Type commands to switch between straight line, arc line, or
spline segments while drawing a polyline.

Drawing an equation-based curve: Any line that can be described by an equation in three
dimensions can be drawn.

Drawing a Sphere: Draw a sphere, a 3D circle, by selecting a center point and a radius.
Spheres are drawn as true sur- faces in the modeler.

Drawing a Spiral: A spiral is a 2D or 3D spiral object created by sweeping an object around a

vector. Sweeping a ID object results in a 2D sheet object. Sweeping a 2D sheet object results
in a 3D solid object.

Drawing a Bond wire: A bond wire is a thin metal wire that connects a metal signal trace with
a chip. Please see the topic Bond wires in the Technical Notes before drawing a bond wire.

Drawing a Point: Drawing a point object within the problem region enables you to plot fields
or perform field computations at that point. Points are always considered on-model objects by
the modeler.

Drawing a Plane: A plane object is a cut plane through the problem region. You can plot fields
or perform field computations on their surface. Planes are always considered non-model objects
by the modeler.

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Rotating objects: Rotate objects about the X, Y, and Z-axis using the Edit>Arrange>Rotate
command.

Mirroring objects: Mirror an object about Edit>Arrange>Mirror command a plane using the

Edit>Arrange>Mirror command.

3.2.3 Status bar:

The status bar is located at the bottom of the application window. It displays information about
the command currently being performed.

To display or hide the status bar: Click View> Status Bar.

Depending on the command being performed, the status bar can display the following:

X, Y, and Z coordinate boxes.

A pull-down list to enter a point's absolute, relative, cartesian, cylindrical, or spherical

coordinates. The model's units of measurement.

3.2.4 Project manager:

The Project Manager window displays the open project's structure, which is referred to as the
project tree The Project Manager window displays details about all open HFSS projects. Each
project ultimately includes a geometric model, its boundary conditions and material
assignments, and field solution and post-processing information To show or hide the Project
Manager window, do one of the following:

Click View> Project Manager.

A check box appears next to this command if the Project Manager window is Visi Right-click
in the toolbars area on the desktop, and then click Project Manager on the short cut menu.

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 Figure 3.2 Project Manager

Viewing HFSS Design Details

Once you insert an HFSS design into a project, it is listed as the second node in the project tree.
It is named HFSS Model by default, where n is the order in which the design was added to the
project. Expand the design icon in the project tree to view all of the specific data about the
model, including its boundary conditions and material assignments, and field solution and post-
processing information. The HFSS Model node contains the following project details:

Boundaries: Displays the boundary conditions assigned to an HFSS design, which specify the
field behaviour at the edges of the problem region and object interfaces.

Perfect E: Represents a perfectly conducting surface.

Perfect H: Represents a surface on which the tangential component of the H-field is the same
on both sides.

Impedance: Represents a resistive surface.

Radiation: Represents an open boundary using an absorbing boundary condition (ABC) that
absorbs outgoing waves.

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PML: Represents an open boundary condition using several layers of specialized materials that
absorb outgoing waves. Finite Conductivity: Represents an imperfect conductor.

Symmetry: Represents a perfect E or perfect H plane of symmetry.

Master: Represents a surface on which the E-field at each point is matched to another surface
within a phase difference.

Slave: Represents a surface on which the E-field at each point has been forced to match the E-
field of another surface to within a phase difference.

Lumped RLC: Represents any combination of lumped resistor, inductor,and/or capacitor in

parallel on a surface.

Excitations: Displays the excitations assigned to an HFSS design, which are usedto specify
the sources of electromagnetic fields and charges, currents, or voltages on objects or surfaces
in the design. Excitations in HFSS are used to specify the sources of electromagnetic fields and
charges, currents, or voltages on objects or surfaces in the design.

Wave Port: Represents the surface through which a signal enters or exits the geometry.
Lumped Port Represents an internal surface through which a signal enters or excites the
geometry.

Incident Wave: Represents a propagating wave impacting the geometry.

Voltage Source: Represents a constant electric field across feed points.

Current Source: Represents a constant electric current across feed points.

Magnetic Bias: Used to define the net internal field that biases a saturated ferrite object.

Mesh Operations: Displays the mesh operations specified for objects or object faces. Mesh
operations are optional mesh refinement settings that are specified before a mesh is generated.

3.2.5 Properties Window

The Properties window displays the attributes, or properties, of an item selected in the project
tree, the history tree, or the 3D Modeler window. The Properties window enables you to edit
an item's properties. The properties, and the ability to edit them in the Properties window, will
vary, depending on the type of item selected.

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 Figure 3.3 Properties Window

3.2.6 Progress Window:

The Progress window monitors a simulation while it is running. To display or hide the Progress
window, do one of the following:

Click View>Progress Window.

A check box appears next to this command if the Progress window is visible. Right-click the
history tree, and then click Progress on the shortcut menu. A check box appears next to this
command if the Progress window is visible.

3.2.7 Message Manager:

The Message Manager displays messages associated with a project's development, such as
error messages about the design's setup or \informational messages about the progress of
analysis. Error messages contain timestampswitha precision of seconds

To display or hide the Message Manager:

Click View>Message Manager

A check box appears next to this command if the Message Manager is visible.

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3.2.8 3D Modeler Window:

The 3D Modeler window is the area where you create the model geometry. It appears to the
right of the Project Manager window after you insert an HFSS design to a project. The 3D
Modeler window consists of the model view area, or grid, and the history tree as shown.

Figure 3.4 3-D Modular Window

To open a new 3D Modeler window, do one of the following:

* Insert a new HFSS design into the current project.

* Double-click an HFSS design in the project tree.

The model you draw is saved with the current project when you click

File>Save. Objects are drawn in the 3D Modeler window. You can create 3D

objects by using HFSS's Draw menu commands or you can draw ID and 2D

objects, and then manipulate them to create 3D objects. For more information, see Drawing a
Model.

3.2.9 History Tree:

History Tree lists all the active model's structure and grid details

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 Figure 3.5 History Tree

Invalid: Lists all invalid objects

Objects: Displays all the model's objects and the history of the commands carried out on each
object. By default, HFSS groups object by material. you can change this by selecting the
Objects icon in the history tree and right-click to display the shortcut menu with the Group
Objects by Material checkbox.

Sheets: Displays all the sheets in the model 3D design area. By default, HFSS groups sheet
objects by boundary assignment. You can change this by selecting the Sheet icon in the history
tree and right-click to display the shortcut menu with the Group Sheets by Assignment
checkbox.

Lines: Displays all line objects included in the active model. See Drawing a Straight Line for
information on how to draw a line object.

Points: Displays all point objects included in the active model. See Drawing a Point for
Coordinate Systems: Displays all the coordinate systems for the active model. See Setting
Coordinate Systems for more information on this model detail.

Planes: Displays the planes for all the coordinate systems. When you create a coordinate
system, default planes are created on its XY, YZ, and XZ planes

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 CHAPTER-4
SIMULATIONS AND METHODOLOGY

4.1 DESIGNING OF MICRO STRIP ANTENNA

4.1.1 INTRODUCTION
In preparation for the design and simulation of our 4x4 planar antenna array, we adopted a
methodical approach by first focusing on the development of a single microstrip patch antenna.
This decision was driven by the need to gain valuable insights into the anticipated performance
of the larger antenna array. By simulating and analysing the microstrip patch antenna, we aimed
to establish a preliminary understanding of the expected results and performance
characteristics. By taking this step-by-step approach, we aimed to ensure the success and
effectiveness of our overall antenna design process, ultimately leading to the development of a
high-performance 4x4 planar antenna array that meets the requirements and expectations of
our project goals.

Figure 4.1 Microstrip Patch Antenna

4.1.2 SELECTION OF SUBSTRATE

In our project, we aim to simulate a 4x4 planar antenna array within the frequency range of 7
GHz to 12 GHz, with a focus on applications in the X-Band. To enhance the gain and optimize
the performance of our antenna array, we have chosen RT/Duroid as the substrate material.

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RT/Duroid is selected for its favourable dielectric properties, low loss characteristics, and
dimensional stability, which are crucial for achieving optimal antenna performance in the X-
Band frequency range. By using RT/Duroid as the substrate for our antenna array, we aim to
leverage its excellent electrical properties to maximize the efficiency and
effectiveness of our design.

Reduced Dielectric Losses: RT/Duroid boasts a low dielectric constant (εr) which translates to
lower capacitance in the antenna. This directly reduces dielectric losses within the substrate,
allowing more signal energy to be radiated outward, contributing to higher gain.

Improved Efficiency: The low loss tangent (tan δ) of RT/Duroid minimizes resistive losses that
would otherwise dissipate signal power as heat within the substrate. This translates to a more
efficient antenna that can convert more input power into radiated energy, again leading
to enhanced gain.

Dimensional Stability: Throughout operation, the antenna array experiences temperature

variations. RT/Duroid's excellent dimensional stability ensures the antenna elements maintain
their designed shapes and spacing. This stability is vital for consistent antenna performance
and maintaining the gain enhancement achieved through the array design.

4.1.3 DIMENSIONS OF MICRO STRIP PATCH

Parameter Dimensions

Substrate Thickness 1.6 mm

Patch Length 2.5 mm

Patch Width 2.5 mm

50Ω Feeding Line 0.5 mm

100Ω Feeding Line 0.22 mm

Table 4.1 Dimensions of Micro Strip Patch Antenna

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4.1.4 Feeding Implementation
In our project, we aim to simulate a 4x4 planar antenna array within the frequency
range of 7 GHz to 12 GHz, with a focus on applications in the X-Band. To enhance the
gain and optimize the performance of our antenna array, we have chosen RT/Duroid
as the substrate material. RT/Duroid is selected for its favourable dielectric properties,
low loss characteristics, and dimensional stability, which are crucial for achieving
optimal antenna performance in the X-Band frequency range. Overall, our decision to
use RT/Duroid as the substrate material for both the microstrip patch antenna and
the 4x4 planar antenna array underscores our commitment to achieving optimal
performance and efficiency in the X-Band frequency range. Through careful analysis
and simulation, we aim to leverage the unique properties of RT/Duroid to develop a
high-gain antenna array that meets the demands of our intended application.

Figure 4.2 Port

4.1.5 Antenna Modelling

We began with by defining the specifications of the microstrip patch antenna similar to the 4 x
4 Planar Antenna Array. We chose the appropriate substrate material for the microstrip patch
antenna. Consider factors such as dielectric constant, loss tangent, and dimensional stability. In
this case, select RT/Duroid for its favourable dielectric properties and low loss characteristics.
We calculated the dimensions of the patch antenna based on the desired operating frequency
and substrate properties. Use equations or numerical methods to determine the length, width,
and feed point location of the patch. Determining the width and length of the feed line to
achieve the desired impedance matching and feed point location.

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4.2 DESIGNING OF PLANAR ANTENNA ARRAY
4.2.1 INTRODUCTION
In our project, we embark on the design of a planar antenna array system. The planar antenna
array, like its microstrip counterpart, represents a crucial component in modern communication
and radar systems, offering versatile performance and adaptability across various applications.
By leveraging advanced design techniques and simulation tools, we aim to develop a high-
performance planar antenna array that meets the demands of our intended X-Band application.
Through a systematic design process, we aim to optimize the performance of the planar antenna
array, fine-tuning design parameters to achieve the desired performance metrics. Parametric
studies and optimizations enable us to refine the design and ensure compliance with
specifications.

Figure 4.3 4 X 4 Planar Antenna Array

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4.2.2 DIMENSIONS OF PLANAR ANTENNA ARRAY

Parameter Dimensions

Substrate Thickness 1.6 mm

Substrate Length 60.5 mm

Substrate Width 60.5 mm

Patch Length 2.5 mm

Patch Width 2.5 mm

50Ω Feeding Line 0.5 mm

100Ω Feeding Line 0.22 mm

Table 4.2 Dimensions of 4 x 4 Planar Antenna Array

4.2.3 SELECTION OF SUBSTRATE

In our project, we intend to simulate a 4x4 planar antenna array operating in the X-Band
frequency range of 7 GHz to 12 GHz. To optimize the antenna array's performance, we have
selected RT/Duroid as the substrate material due to its favourable dielectric properties, low loss
characteristics, and dimensional stability. By utilizing RT/Duroid as the substrate, we aim to
capitalize on its exceptional electrical properties to enhance the efficiency and effectiveness of
our antenna design.

RT/Duroid offers several advantages for our antenna design. Firstly, its low dielectric constant
(εr) results in reduced capacitance within the antenna, leading to lower dielectric losses and
higher signal energy radiation, consequently contributing to increased gain. Secondly, the low
loss tangent (tan δ) of RT/Duroid minimizes resistive losses, ensuring that more input power is
converted into radiated energy, thus further enhancing gain. Additionally, RT/Duroid's
excellent dimensional stability ensures that the antenna elements maintain their intended shapes
and spacing, crucial for consistent antenna performance and maintaining the gain enhancement
achieved through the array design. Overall, the selection of RT/Duroid as the substrate material

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promises to optimize the performance of our 4x4 planar antenna array for X-Band applications.

Table 4.4 Dimensions of 4 x 4 Planar Antenna Array

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 CHAPTER-5

SIMULATION AND RESULTS

5.1 Single Microstrip Patch Antenna Results:

In the simulation and results section, we explore how simulation helps us understand our
antenna's behaviour before physical testing. Using electromagnetic simulation software, we
input our design parameters to predict radiation pattern, impedance matching, and gain. We
present the outcomes, including graphs and data, and analyse them to evaluate our antenna's
performance against specifications. Comparing simulated and experimental results ensures
accuracy. This section provides valuable insights into our antenna's performance, guiding
further optimizations and discussions.

5.1.1 S11 parameter

The reflection coefficient, denoted as S11, serves as an indicator of the extent to which radio
frequency (RF) waves undergo reflection upon transmission through an antenna. A reduced
S11 value signifies enhanced performance, indicating minimized power reflection. Conversely,
an elevated S11 value implies increased power reflection, indicative of a less efficient system.
The return loss characteristics for single microstrip patch antenna shows that the antenna
resonating at 11.93GHz. The return loss characteristics show that the single microstrip patch
antenna is resonating for multiple frequencies at 11.93GHz and 11.51GHz with gains of
-47.77dB and -9.92dB.

Fig. 5.1 The S Parameter Plot

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5.1.2 Radiation Pattern

The radiation pattern of an antenna is a graphical representation of the power radiated by the
antenna in different directions. It is typically plotted in a polar coordinate system, with the
antenna at the centre and the angle from the antenna axis on the horizontal axis. The power
radiated in a particular direction is represented by the distance from the centre of the plot to the
curve. The radiation pattern of 4x4 planar patch antenna array is shown below Fig.

Fig. 5.2 The Radiation Pattern at 00 Fig. 5.3 The Radiation Pattern at 900

5.1.3 Gain Plot

It is defined as the proportion of intensity of the radiation in a particular direction to the

obtained intensity of radiation. If maximum power is radiated in the desired direction and
minimum power is radiated in undesired directions, then the maximum gain is obtained for an
antenna. It can be observed that the gain is very low at notch bands. The gain of the antenna is
nearly constant and at notch bands, the gain is drastically reduced. The gain plot of the 4x4
planar antenna array is shown in the below figure.

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 Fig. 5.4 Gain Plot of Single Patch Antenna

5.2 4 X 4 Planar Antenna Array Results:

5.2.1 S11 parameter

The return loss characteristics for single microstrip patch antenna shows that the antenna
resonating at 8.6 GHZ. The return loss characteristics show that the single microstrip patch
antenna is resonating for multiple frequencies at gains of 9.7 dB.

Fig. 5.5 The S Parameter Plot

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5.2.2 Radiation Pattern

Radiation pattern is plot of radiated power density to angle. The radiation pattern is a 3D plot
or 2D plot. i.e., 𝑃𝑟𝑎𝑑 𝑉𝑠 𝜃,or 𝑃𝑟𝑎𝑑 𝑉𝑠 𝜑.

Fig. 5.6 The Radiation Pattern at 00 Fig. 5.7 The Radiation Pattern at 900

5.2.3 Gain

The ratio of the intensity, in a given direction, to the radiation intensity that would be obtained
if the power accepted by the antenna were radiated isotopically. If the efficiency is not 100
percent, the gain is less than the directivity. The 4 X 4 Planar Array Antenna has a gain of 9.7.

Fig. 5.7 Gain Plot of 4 X 4 Planar Array Antenna

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 CHAPTER-6

CONCLUSION AND FUTURE SCOPE

6.1 CONCLUSION
In conclusion, our project focused on the design and optimization of a 4x4 planar
antenna array for applications in the X-band frequency range. Through meticulous design and
simulation, we successfully developed a high-performance antenna system capable of
achieving substantial gains in signal strength and overall performance. By leveraging advanced
design techniques and simulation tools, we were able to fine-tune the antenna parameters to
meet the desired specifications and performance metrics.

Our project also highlighted the importance of substrate selection in antenna design,
with RT/Duroid emerging as a favourable choice due to its excellent dielectric properties, low
loss characteristics, and dimensional stability. By utilizing RT/Duroid as the substrate material
for our antenna array, we were able to maximize the efficiency and effectiveness of our design,
particularly in the X-Band frequency range.

Additionally, our decision to first design and simulate a single microstrip patch antenna
provided valuable insights into the expected performance of the larger antenna array. Through
careful analysis and comparison of the results obtained from the microstrip patch antenna with
those expected from the planar antenna array, we were able to validate the suitability of our
design approach and substrate selection.

Furthermore, our project demonstrated the importance of systematic design and

optimization processes in antenna engineering. By following a structured approach and
iterating on the design parameters through simulation and experimental validation, we were
able to achieve optimal performance and meet the project goals.

In summary, our project represents a significant step forward in the development of

high-gain planar antenna arrays for communication and radar applications. Through innovative
design techniques, substrate selection, and rigorous optimization processes, we have
successfully developed a robust antenna system that meets the demands of modern
communication systems in the X-Band frequency range.

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6.2 FUTURE SCOPE
Looking to the future, our project lays the groundwork for several avenues of further
exploration and research in the field of antenna engineering. One potential area for future study
is the optimization of design parameters to further enhance the performance of planar antenna
arrays. This includes investigating alternative substrate materials, refining feeding techniques,
and exploring novel antenna configurations to achieve even higher gains and efficiency. With
its enhanced performance and adaptability, our designed 4x4 planar antenna array holds
considerable potential for deployment in a wide range of practical scenarios.

• Wireless Communication: Our antenna array can improve signal strength, coverage,
and reliability in wireless networks, Wi-Fi systems, and cellular networks.
• Satellite Communication: In satellite communication systems, our antenna array can
facilitate reliable communication links between satellites and ground stations, enabling
the transmission of voice, data, and video signals over long distances.
• Radar Systems: Our antenna array's beamforming capabilities can enhance target
detection, tracking, and surveillance in radar systems, benefiting both civilian and
defence applications.
• Aerospace Platforms: The versatility of our antenna array makes it suitable for
deployment in aerospace platforms such as UAVs and satellites, enabling efficient
communication and sensing capabilities.
• Internet of Things (IoT): Our antenna array can be integrated into IoT networks, smart
grids, and autonomous vehicles, where robust and efficient communication systems are
essential for data transmission and connectivity.

Additionally, advancements in simulation tools and optimization algorithms offer opportunities

to further streamline the design process and accelerate innovation in antenna technology.
Furthermore, as emerging technologies continue to shape the landscape of communication and
radar systems, there is a growing need for antenna solutions that can adapt to changing
requirements and frequencies. By continuing to push the boundaries of design and
optimization, our project paves the way for future developments that will continue to drive
progress and innovation in the field of antenna engineering. Overall, the future scope of our

RAGHU INSTITUTE OF TECHNOLOGY 52

project extends to diverse domains, offering opportunities for innovation and impact in
addressing real-world communication and sensing challenges.

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 REFERENCES

[1] L. Wang, J. Wang and J. Shi, "Design of 4×4 meandering-fed stacked patch antenna array,"

2018 International Workshop on Antenna Technology (iWAT), Nanjing, China, pp. 1-3, 2018.

[2] P. Mathur and M. Arrawatia, "High Gain Series fed Planar Microstrip Antenna Array using

printed L—probe feed," 2020 IEEE International Symposium on Antennas and Propagation

and North American Radio Science Meeting, Montreal, QC, Canada, pp. 589-590, 2020.

[3] P. Aggarwal, S. Pani and P. Saxena, "Design and Analysis of 2 x4 Planar Array Antenna

with Beam Steering Facility," 2018 International Conference on Emerging Trends and

Innovations In Engineering And Technological Research (ICETIETR), Ernakulam, India, pp.

1-4, 2018.

[4] T. Zhang, L. Chen, A. U. Zaman and J. Yang, "Ultra- Wideband Millimeter-Wave Planar

Array Antenna With an Upside-Down Structure of Printed Ridge Gap Waveguide for Stable

Performance and High Antenna Efficiency," in IEEE Antennas and Wireless Propagation

Letters, vol. 20, no. 9, pp. 1721-1725, Sept. 2021.

[5] Y. -Q. Zhang, X. -P. Li, Y. -B. Dang, X. -Y. Song, H.

-L. Yang and Y. -P. Li, "Compact Planar Antenna Array for X-Band Communication

Applications," 2021 13th International Symposium on Antennas, Propagation and EM Theory

(ISAPE), Zhuhai, China, pp. 1-3, 2021.

[7] N. Parthasarathy and R. Abhari, "A Compact 2 by 2 Printed Yagi-Uda Antenna Array with

Enhanced Isolation and Gain," 2019 IEEE International Symposium on Antennas and

Propagation and USNC-URSI Radio Science Meeting, Atlanta, GA, USA, pp. 1761-1762,

2019.

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[8] H. A. Diawuo and Y. -B. Jung, "Broadband Proximity-Coupled Microstrip Planar Antenna

Array for 5G Cellular Applications," in IEEE Antennas and Wireless Propagation Letters, vol.

17, no. 7, pp. 1286-1290, July 2018.

[9] S. Kim and J. -I. Kim, "A Circularly Polarized High- Gain Planar 2 × 2 Dipole-Array

Antenna Fed by a 4-Way Gysel Power Divider for WLAN Applications," in IEEE Antennas

and Wireless Propagation Letters, vol. 18, no. 5, pp. 1051-1055, May 2019.

[10] Y. Andreev, V. Koshelev and S. Smirnov, "Characteristics of an Ultrawideband 8x8 Array

of Cylindrical Helical Antennas," 2018 20th International Symposium on High-Current

Electronics (ISHCE), Tomsk, Russia, pp. 66-69, 2018.

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