CHAPTER-II

REVIEW OF LITERATURE
 REVIEW OF LITERATURE

Design and development of patch antenna for wireless communication has been discussed in
this section. As it has been known that patch antenna can be placed on PCB for various
communication devices. So, keeping this in mind researchers worked on various patch
antenna designs for wireless applications. Patch antenna has been discussed according to their
application in various fields of wireless communication such as bio-telemeter, data telemeter
wireless sensor networks and other wireless applications.

Salvador et al. (1995) reported patch antenna that can be utilized in S and X bands
applications which has array of four patches arranged in such a manner that there is spacing
between two patches. A new configuration of patch antenna is introduced, which provides a
dual-band operation. With four- square patches printed in the empty spaces this
structure is consists of S-band cross patch among the arms of the cross. These patches
worked at X-band providing a sub array which is simple to design, having the advantage to
be print on a single layer. The geometry of an array is used to design the above structure, is
suggested. This can be suitable for satisfying the requirements of a typical dual-frequency
SAR antenna.

Fayyaz et al. (1998), reported a rectangular patch antenna for dual frequency operation in
which designed antenna was fed by a microstrip line on the onside of the radiating patch
while on other side of edge is shorted. In 1998, Au et al reported the aperture coupled stacked
rectangular patch antenna and obtained 45% bandwidth by optimizing the dimensions and
location of the patches. In the same year, N.Herscovici presented the typical single-layer
patch printed on a dielectric substrate which was narrow band element.

Jan (2001) reported a dual-frequency circular MSA design using single-layer, single-feed and
loaded with open ring slot was reported. In 2001, Waterhouse Presented a large bandwidth
and low profile printed phased arrays of aperture coupled stacked patch antenna useful in
radio-astronomy.

Lazzi et al. (1998), investigated experimental and numerical results for high gains, low SAR
signal band and dual band microstrip patch antennas covering the frequency band (825 -895
MHz and1830-1930 MHz. The presence of the human head and hand significantly alter the
performance of cellular telephones. Human body absorb a fraction of power (30-70 %) which
effects antenna efficiency causing drastic reduction and SAR concerns. Microstrip patch
antenna would reduce the problem by using by using of high gain without decreasing in
radiating performance of the cellular phone leading to low SARs designed in laboratory (825-
895 & 1850-1930 MHz i.e. covering the wireless bands). As a result, these antennas
comparing with cellular telephones are characterized by radiating performance with the
handset simulated mounted on a box. Comparing with typical whip antennas and the handset
equipped human head induce very low SARs. The patch antenna requires less power so
longer battery life because of reduced absorption in the head having lower SARs.
Lelaratne and Langley (2000), investigated a single layer, multi band microstrip patch
antenna operating over the frequency 1.6-2.5 GHz. Launching new mobile satellite
communication links for data applications telephone demands development of low-profile
and low-cost small antennas. Multiband microstrip patch antenna operates at frequency range
between 2.5 and 1.6 GHz of Globastar satellite and Iridium communication systems. The
resonant modes TM₁₀ and TM ₃₀ operates with circular
polarization. The antenna excites by shaping the corners of the patch and combination of slots
cut into the patch, the unwanted TM₂₀ is suppressed. Frequency band
separations can be varied significantly from 1.3 to 2.5×the lower frequency. Data for
designing the patch dimensions is presented. The return loss, impedance characteristics and
radiation patterns are presented for a practical design
Tong et al. (2001), investigated a dual band antenna for DCS and GSM applications. The two
dielectric substrates were overlapped for its radiating structure. Thereafter, Shum and Luk et
al. reported dual band L-probe patch antenna operating in GSM/PCS systems.

Villegas et al. (2002), A dual band patch antenna using parallel genetic–algorithm for
wireless communication was used of genetic algorithm is arrived at an optimal
(counterintuitive) design of wireless communication applications (operating at 1.9 and 2.4
GHz) for a dual-patch antenna. To this end, we combine the evolutionary optimization
approach of the robustness and the accuracy of MoM full-wave solutions having the speed of
parallel processing in an electromagnetic GA optimization application (EGO). Maintaining a
low cross-polarized the goal is achieved having an acceptable input VSWR by designing a
descendant of the E-patch antenna. To this end, an appropriate hybrid fitness function is
employed in the GA. Field and S₁₁ measurements of various GA (Genetic
algorithm) based optimized patch configurations exhibit good agreement with the MoM
calculations.
Chen et al. (2003), reported the planar inverted-F antenna (PIFA) for the dual band
applications and founded that maximum antenna gain of 2.5 dBi for both 900/1800 MHz
band operations.

Khodier and christoulou et al. (2003), investigated a stacked microstrip antenna using
FDTD method and obtained a bandwidth of 35% with almost constant antenna’ radiation
characteristics. Later Buja and Syakhal demonstrated a low-profile triple patch stacked
antenna with impedance bandwidth of 22%.

Yeh et al. (2003), reported compact dual bond planes inverted F-shaped antenna GSM/DCS
application. Dual band mobile phone is proposed and implemented using compact dual-band
planar inverted F-shaped antenna which is suitable for the application in digital
communication system/mobile communication (DCS/GSM). An antenna proposed has three
resonant elements have slightly different lengths of two meandered strips and one nearly-
rectangular patch, which are printed on a supporting FR4 substrate and arranged in a compact
configuration. A common shorting pin is shared by three resonant elements. For the GSM
(890-960 MHz) operation the two meandered strips both resonated as a quarter-wavelength
structure is operated for the proposed antenna. Three resonant modes are generated from the
upper band of the proposed antenna, one from the nearly rectangular patch which is leading
to a wide bandwidth (DSC band 1710- 1880 MHz) two from the second modes of the second
higher order of the two meandered strips. The proposed antenna design and experimental
results are presented.

Chen et al. (2004), reported the PIFA antenna for the dual band operation in mobile
communication and investigated that maximum antenna gain of 2.5 dBi for both 900/1800
band operations.

Jung and De Flaviis (2004), demonstrated dual frequency operation for WLAN (Wireless
Local Area Network) applications. For application a rectangular patch with 4-bridges is used.
Ho-Yung Kim et al. (2004), reported patch antenna with shorting wall for wireless
applications. Afterwards, S.H. Choi et al. demonstrated dual frequency patch which have
backed microstrip line for medical, scientific and industrial. The radiation patterns at 2.4 and
5.8 GHz is measured. For applications of the ISM band a new dual-band antenna is proposed
and designed to operate at 2.4 and 5.8 GHz. By using meandering technique, the lower
frequency band (2.4 GHz) can be obtained. By embedding a baked microstrip line for dual-
band operation the upper-frequency band (5.8 GHz) was achieved. Details of the proposed
antenna design and experimental results are presented and discussed. The measured radiation
patterns at 2.4 and 5.8 GHz and antenna gain across the respective frequency bands are also
presented. After that, dual frequency MSA for high precision for GPS application was
reported by Broccia et al.

Hwang et al. (2005) demonstrated dual-band printed antenna for PCS (1750-1870 MHz)
band. Maximum radiation gains are measured (0.94 and 1.89 dBi) for lower Q appear
resonance frequency respectively. An internal dual-band antenna which has a planar-type
radiator and operates at the CDMA (824–894-MHz) and PCS (1750–1870-MHz) bands. By
tuning the size and the length of the strip lines radiating segments the antenna characteristics
at each band are optimized. FR-4 substrate material is used for antenna of thickness 1mm,
500 coaxial feeding cable and a planar-type radiator. In the CDMA & PCS bands
respectively. The maximum measured radiation gains are 0.94 and 1.89 dBi.

Shivnarayan and Vishvakarma (2005), notch on the rectangular patch is designed. Its
theoretical analysis and observation due to the notch loading was the frequency ratio
variation. In a single design a noval dual-band square microstrip patch antenna is proposed
for antenna size reduction and improvement of bandwidth which can be operate at 1.7 GHz
and 5.5 GHz dual frequencies. The basic parameters of an antenna such as return loss,
radiation pattern, gain, polarization and bandwidth are obtained. Using ZELAND IE3D
version 12.0 as a simulation tool which is analyze and optimize. Square piece antenna has
achieved less return loss of -40 dB in two bands with bandwidth of 40 MHz and 200 MHz
respectively.

Lin & Huang et al. (2005), A compact antenna was proposed and observed the S11 mode are
generated through square patch while S12 mode is activated by angular patch.

J.W. Wu et al. (2005), Investigated rectangular slot loaded antenna for dual-broadband
operation in wireless local area network WLANs and obtained impedance bandwidth for two
resonating frequency 2.4GHz and 5GHz as 11% and 24.6% respectively. Afterward, Zheng
and Fang demonstrated dual characteristic on loading two L-designed lower rectangular
antenna for wireless communication devices. Further, Chang et al. proposed planar quasi -
Yagi antenna of wireless application and observed that antenna had dual band operation.

Wong et al. (2006) designed antenna which has the radiating structure of T- shaped which
generates two resonating modes having the radiating patch greater than ground plane. In same
year, Sze et al. proposed a circular aperture antenna with slit back patch excited by CPW fed.
The broadside far field pattern at both frequency bands was observed.

Lim and Leung et al. (2006), demonstrated dual wide-band rectangular dielectric resonator
antenna (BRA). The parameters of the antenna such as antenna gain, pattern radiation and
return loss was measured. A dual and wideband single-element rectangular dielectric
resonator antenna (DRA) was investigated experimentally which is excited by a microstrip
aperture. It provides two passbands in the ranges of 2.21–2.855 GHz and 4.385–5.455 GHz,
which are popular bands for WLAN. The antenna gain, radiation pattern and return loss of
the proposed configuration are measured.

Joseph et al. (2006), proposed a compact dual band antenna for GSM and Bluetooth
applications with linear polarization. A compact dual-band antenna operating in the 1.8/2.4-
GHz bands with identical linear polarization suitable for DCS/2.4-GHz WLAN applications
is presented. Microstrip-fed printed monopole with an additional strip the proposed
configuration is modified with opposite side of the substrate having a proper truncated
ground plane. The proposed antenna of dimensions 35 × 47 × 1.6 mm offers 2:1 VSWR
bandwidths of 10.8% and 9.8% in the DCS and 2.4-GHz WLAN bands respectively.

Guterman et al. (2006) designed dual-band E-shaped radiating surface back to back antenna.
It can be embedded in laptops and observed two frequency can be tuned at 1.2 to 3.5 GHz,
frequency. In the same year, Pandey and Vishvakarma present the theoretical and simulation
investigations of an E-shaped patch antenna applicable in modern mobile communications. It
showed marked improvement in the bandwidth when compared with rectangular patch
antenna with acceptable radiation pattern.

Khaleghhi (2007) Reported dual-band antenna for WLAN having meander line with backed
ground plane. 11% and 6% impedance bandwidth are measured for lower frequency and
upper resonance frequency. A back coupled rectangular patch and a shaped ground plane is
described as a printed meander line antenna. In the frequency range of 2.4-2.48 GHz and
5.15-5.35 GHz the prototype is proposed for WLAN applications. Resonance impedance
matching, dual-band operation and wide impedance bandwidth are the characteristics of the
antenna. The antenna impedance matching for the first-resonance is provided by applying a
shaped ground plane. In a single design a noval dual-band square microstrip patch antenna is
proposed for antenna size reduction and bandwidth improvement which can operate at dual
frequencies of 1.7 GHz and 5.5 GHz. By adding a rectangular patch, the second even-mode
resonance is generated at the back of the meander antenna. A return loss less than -10 dB of
impedance bandwidth is 11% for the first and 6% for the second resonance. The requirements
for the IEEE 802.11a WAN i.e. 5.15-5.35 GHz and 5.470-5.725 GHz or 5.725-5.825 GHz are
fulfilled by tuning the length of the rectangular patch of second-resonance frequency. In fact
the second-resonance frequency can be adjusted between 5.2 and 7 GHz continuously with a
little effect on the first-resonance.

Wong et al. (2007) designed antenna in such a way that narrow strip generates higher
frequency bands whereas other generate lower frequency band and antenna work for
personnel assistant (PDA).

Chou et al. (2007), presented the analysis of patch antenna design for WLAN and DSRC
applications using genetic algorithm. For the applications of WLAN dedicated to short-range
communication (DSRC), a dual band patch antenna is designed. Inside the antenna structure
shorting plate and shorting pin is used to minimize the antenna size. To create dual-band
operations slots are cut on the patch surface of an antenna. In order to accelerate the antenna
design procedure and to optimize the antenna performance, a genetic algorithm base program
in conjunction with IE3D simulation software is used to optimize the performance of an
antenna and auto-adjust the geometric parameters of the patch. By observing operations of
bandwidth and input impedance of the antenna. Utilizing natural selection method, the new
values of the parameters are generated. Simulated and measurement results shows
distinguished antenna performances while retaining relatively small antenna.
Sim and Tu et al. (2007), proposed slotted planner inverted-F antenna (PIFA) for WLAN
application. Latter Huang et al. studied dual frequency narrow-strip antenna excited by
electromagnetically coupled fed for WLAN. 3.4% and 13% bandwidth for both upper and
lower resonance frequency is measured.

Tao et al. (2007), demonstrated dual-band slot antenna for WLAN application. Radiation
pattern, gain and its impedance bandwidth is investigated experimentally.

Encheng et al. (2007), studied printed microstrip antenna for dual frequency and observe
organic materials dielectric substrate for WLAN communication.

Ren et al. (2007) demonstrated a compact T- shaped patch antenna for wireless
communications. Thereafter, W. C. Liu presented G-shape patch with CPW feed for dual
band operation.
Chang et al. (2008) presented compact vertical patch antenna for WLAN operation. Later,
Inside the antenna structure shorting plate and shorting pin is used to minimize the antenna
size. To create dual-band operations slots are cut on the patch surface of an antenna. The
antenna is consist of mainly shorted patch and driven patch. Both of them are wind along
with two concentric circles. A proposed prototype is demonstrated with 2.4 and 5.4 GHz
WLAN bands. Across the operating bands good broadside radiation characteristics are
observed. Details of the proposed patch antenna and experimental results are presented and
discusses Callaghan and Batchelor proposed disk shaped antenna with shorting wall at the
edges of the patch and fundamental modes is generated at 37 mm of air as substrate.

Rmili and Floch (2008), demonstrated the design V-shaped patch for DCS/ Bluetooth
applications. The proposed antenna is designed for dual-band DSC1800 and 2.4 GHz WLAN
operations. It is a simple surface-mountable monopole antenna. By folding a metallic strip
into V-shape the antenna was obtained soldering with 50-Ω microstrip feed line printed on a
metallized substrate. By adjusting the length of the two metallic strips separately the desired
lower and upper bands can be controlled easily for the proposed antenna. Latter, Ren
proposed the patch antenna that covers the required bandwidth of (2.4-2.485 GHz) and (5.15-
5.825 GHz) with satisfactory radiation characteristics.

Lee et al. (2009), presented U-shaped patch antenna for wireless communications.
Subsequently, Zhang et al. reported double T-shaped slot antenna for radio frequency
identifications applications. Thereafter, Zeng and Chu presented a slotted coupled antenna for
dual band passive radio frequency identification (RFID).

Choi et al. (2009), designed a novel K-shaped patch antenna for WLAN application. The
gain ranging between 3.66 to 4.58 dBi is measured. After then, Wang et al. described about
the use of organic material as dielectric substrate for printed patch antenna in various wireless
applications.

Liu and Chen (2009) demonstrated twin stepped patch radiators for WLAN applications. A
protruded ground and twin stepped patch radiators are used to obtain a microstrip fed
monopole antenna having wide dual-band operation. Impedance bandwidths 710 MHz (2.32-
3.03 GHz) and 1.56 GHz (4.77-6.33 GHz) with 25mm can excite resonances at the 2.16 and
5.52 GHz bands of the proposed antenna with 32 times of overall size monopole like
radiation patterns and the average gain of 2.9 and 3.5 dBi respectively. These properties make
the antenna suitable for 2.4/5.2/5.8 GHz WLAN applications. After then, Wang et al.
designed electromagnetically coupled antenna for dual band operation which is applicable for
satellite communications. Later, He et al. presented a high gain antenna was designed of a
fork for WLAN application.

Hsu et al. (2010) designed E-shaped patch antenna with two resonating frequency at 2.4 and
3.5 GHz for wireless communication. The design of dual-band, single patch microstrip
antenna covering 2.4 and 3.5 GHz for Wi-Fi and WiMAX applications based on E-shaped
patch is presented. While using cavity model analysis in the procedure of design, the slotted
configuration is treated as the perturbed cavity. It characterizes the resonant frequencies of
corresponding modes. By the help of field distribution resulted from the nodal analysis the
feed point position is determined. A new equivalent circuit model based on the coupled
resonators theory is proposed for analysis purposes. The relationship between cavity model
analysis and antenna resonances is further evidenced by the surface current distributions on
the conductors Latter, Shanmuganantham and Ragharan proposed a novel square patch
antenna for bandwidth improvement and size reduction of the antenna.

Shanmuganantham and Ragharan (2010), proposed a novel square patch antenna for
bandwidth improvement and size reduction of the antenna. A novel dual-band square
microstrip patch antenna, a single design is proposed for antenna size reduction and
bandwidth improvement which can operate at dual frequencies of 1.7 GHz and 5.5 GHz.
Return loss, gain, polarization, radiation pattern and bandwidth are the basic parameters of
the antenna obtained. This square piece patch antenna has less return loss of −40 dB with
bandwidth of 40 MHz and 200 MHz in two bands, respectively.

Park et al. (2010), reported a open stub microstrip antenna for dual frequency operation that
can be used for different wireless applications.

Peng and Ruan et al. (2011) demonstrated an antenna for DSC and Bluetooth application
obtained from dual inverted L-shaped antenna. The antenna is fed through microstrip line. In
this paper a novel microstrip fed dual-band patch antenna having two parasitic invert L stubs
for 2.4/5GHz wireless application is presented. Printed on a dielectric substrate of FR4 with
relative permittivity of 4.4 and thickness of 1mm, and fed by a 50Ω microstrip line,
demonstrated the patch antenna having two parasitic invert L stubs to generate three resonant
modes to cover 2.4/5.2/5.8-GHz wireless local area network (WLAN) bands with satisfactory
radiation characteristics. Experimental and simulated S parameters are presented. Parameters
sweep and simulated radiation patterns are demonstrated. Keywords Patch antenna–
Microstrip fed–Invert L stubs–Dual band–WLAN. Thereafter, Sim and Cai proposed
microstrip fed polygon slot structure for WLAN application. The rectangular patch loaded
with narrow slots which has L-geometric slits for wireless applications.

Esfahlani et al. (2011), designed printed patch antenna fed with coaxial and shorting pin on
the radiating patch obtained the frequency ratio of 4.75. Ma and Row designed the dual band
patch antenna which has two dielectric substrates overlapped each other and excited via a
soma connector.

Sim and Cai (2011), designed microstrip-fed polygon slot antenna for WLAN applications in
the 2.4/5.2/5.8 GHz bands. Panda and Kshetrimayum designed a narrow patch antenna. The
proposed antenna was placed over dielectric substrate excited by microstrip line used for
wireless application. A compact notched CPW-fed wide-slot antenna for WLAN applications
and worldwide interoperability for microwave access (WiMAX) applications was proposed
by Lin et al.

Ansari et al. (2011), designed six vertical and three horizontal slots in such a way that three
U-shaped inside each other and these slots play vital role in deciding the antenna
characteristics. A novel design of broadband patch antenna is presented in this paper. By
choosing appropriate selection of positions and dimensions of slot and notch on the radiating
patch the broadband property of the proposed antenna is achieved. The bandwidth of the
proposed antenna is found to be 30.5% with operating frequency band from 1.56 GHz to
2.12 GHz. Antenna characteristics are observed for different inclination angles “α” and its
effect on bandwidths is also reported. The maximum gain of the antenna is found to be
9.86 dBi and direction of maximum radiation over the operating band broadside radiation
pattern is achieved. The proposed antenna structure is first simulated then fabricated and at
last tested to obtain the desired performance. The experimental results and simulated results
are verified which are in good agreement.

Li et al. (2012), proposed dual band antenna that has L-shaped and arc-shaped stub as
radiating structure. whereas Luo et al. designed a novel compact printed monopole antenna
used for WLAN applications. The proposed antenna consists of an L‐shaped monopole
radiator and an arc‐shaped stub which can produce the required two bandwidths respectively.
This antenna, fed by a 50‐Ω microstrip line, has a small size of only 20 mm × 25 mm. A
prototype of the dual‐band antenna has been designed, fabricated and measured. It is shown
by the presented antenna as a experimental results which covers 2.2-2.6 GHz and 4.7-6.2
GHz having less than -10 dB return loss. The antenna has good radiation patterns in both E
plane and H plane reported dual band antenna for wireless applications which has L-shaped
slots. Leal et al. provided the effective way of reducing size of the patch antenna using U-
shaped resonator.

Lu and Liu (2012), designed reactive loaded array antenna microstrip line fed having 50
with gain of 14.1 dBi for 4G and WiMAX applications. After that, Batra and Sharma studied
the method to combine DRA patch antenna and the aperture utilized for wireless applications.
Further, Salar Rahimi et al. proposed electromagnetic coupled band gap antenna. The
proposed antenna is designed to use using circular patch that are place on dielectric evenly
like an array. Later on, Tan and Ismail designed compact dual band tag antenna for radio
frequency identification (RFID) systems whereas Xiong and Gao proposed the design of
compact dual frequency microstrip antenna in such a way that it can be utilized for multi-
band operation in wireless operations.

Lee et al. (2013), proposed the techniques for size reduction and wide frequency on
microstrip antennas design. For reducing the size of a shorted patch antenna, a technique is
proposed. In this method the notches are positioned near the shorting pin and feed. A shorted
patch is 75% smaller than a conventional microstrip patch antenna utilizing this technique.

Ansari et al. (2013), proposed the analysis of disk-shaped antenna with L-strip feeding. For
analysis circuit theory concept and MoM (Method of Movements) is used. After that,
Moosazadeh and Esmati presented the small planar microstrip-fed square radiator using
slotted conductor backed plane.

Ojaroudi and Ojaroudi (2013), demonstrated reactive loaded patch antenna excited by
coplanar wave guide for wireless communication such as Bluetooth / PCS applications.
Further, Chen et al. observed by investigating an antenna design for UTMS and GPS.
Proposed antenna is loaded with shorting pin on radiating patch. In the same year, Bekali and
Essaaidi has proposed a novel compact reconfigurable patch antenna. The antenna is tuned in
two frequency bands of 3G and 4G mobile communication. Ying song Li et al. observed
microstrip antenna used in shorting wall and capacitance for enhancing the characteristics for
WLAN applications.

Mishra et al. (2013), designed the L- shaped slot on the disk patch radiator and analysis the
results using circuit theory concept. A dual frequency resonance antenna is achieved by intro-
ducing L-shaped slot in circular disk patch. Circuit theory concept is used for analysis. The
resonance frequency 5.087 and 8.455 GHz and bandwidth 10 dB is found from the proposed
antenna. The lower resonance frequency 4.39% & the upper resonance frequency 4.66% is
found. Just by changing the dimensions of notch and slot it is easy to adjust the higher band
and lower band in the antenna introduced. The frequency ratio 1.6621, the gain 9.5 dB at
lower resonance and 7.0 dB at upper resonance frequency, 9.46 and 8.82% as the efficiency
at lower and upper resonance of the proposed antenna is found. The simulated results and
theoretical results are compared with IE3D which are in good agreement.

Boney et al. (2014), reported trapezoidal shaped antenna which has half ground and antenna
is excited by the meander line fed. Antenna is proposed & designed with partial ground and
meander line feed which operates at 1.42–1.62 and 3.49–3.73 GHz simultaneously. It is
suitable for GPS system at 1.5 GHz and 3.5 GHz worldwide interoperability for WiMAX
microwave access frequency bands, respectively. A meandered transmission line is fed to
reduce the overall antenna size. The proposed antenna is fabricated on low cost FR-4
substrate having 1.6 mm thickness consists of a partial ground etched on bottom side of the
strip and a trapezoidal-shaped patch. Moreover, the antenna radiation pattern to
omnidirectional has facilitated using the partial ground plane. Comparing the simulated
result, the antenna is measured to observe the performance i.e. gains of 1.7 and 3.4 dBi with
gain at second frequency band. The experimental results and simulated results are verified
which are in good agreement. Further, Addaci et al. proposed an antenna for dual band
operation which has PIFAs that are placed closed to each other.

Chakraborty et al. (2014), designed rectangular microstrip patch antenna that has two
narrow rectangular apertures on the radiating surface as well as it aperture on the ground
plane which can be utilized for WLAN application. Later, Lin-Chuan Tsai experimented a
bow-tie-shaped CPW-fed slot antenna is consist of coaxial connector and two conducting
strips suitable for wireless communication applications.

Singh et al. (2014), investigated the analysis of symmetrical shorting loaded patch antenna
and symmetrical notches. VSWR and return loss is calculated presenting equivalent circuit
diagram. Singh et al. analysed the half disk patch antenna loaded with shorting pin and
excited via a L-strip feeding using circuit theory concept. Singh et al. proposed the analysis
of F-shaped narrow strip antenna similar to monopole antenna as radiation pattern. Circuit
theory concept is used to analyze the slot loaded compact rectangular patch antennas is
presented theoretically. The parameters of L-shaped fed slot loaded compact rectangular
microstrip patch antenna such as VSW, return loss, radiation pattern have been calculated
theoretically and found that antenna resonates at 2.95 GHz for lower resonance and 6.01 GHz
for upper resonance frequencies. The bandwidth of the antenna at lower resonance frequency
is 10.16% (theoretical) and 1016% (simulated) whereas upper resonance frequency is 2.51%
(theoretical) and 1.5% (simulated). The characteristics of other rectangular patch antennas is
compared with the L-strip fed slot loaded compact rectangular microstrip patch antennas.
Using AWR circuit simulator the circuit diagram of antenna is proposed, fabricated and
simulated. There is a close agreement while measuring the results as theoretical results
compared with IE3D and AWR simulation results.

Sharma et al. (2015) designed π slot on the patch antenna for dual band operation using
aperture feeding and its size reduce on loading the slots. Without compromising efficiency or
miniaturization a dual band dielectric resonant antenna is designed by using a proposed
technique which combines a slot antenna and a dielectric resonator antenna (DRA). The
resonance of the slot and the dielectric structure merged is observed to achieve extremely
wide bandwidth over which the antenna radiation pattern and polarization are preserved. Here
the radiation performance if the DRA by the effect of slot size is studied. The antenna
structure is simulated using two simulators (Ansoft HFSS and CST-Studio software).
Comparing with simulated results and measured results the DRA has a gain of 6 dBi at 6.1
GHz and 5.5 dBi at 8.3 GHz, efficiency 98% and 10dB return impedance bandwidth of about
4% and 6% at two resonating frequencies has been achieved from the configuration. The
radiation properties of DRA are significantly affected by the size of the slot shown.
Simulation and measured results are in good agreement, so can be used for wireless
applications.

Bakariya et al. (2015), proposed the design of non-contacting feeding to patch i.e.,
electromagnetic coupling between the V-shaped radiating patch and fed microstrip, it can be
utilized for wireless applications such as Bluetooth, WiMAX, and WLAN.

Liu et al. (2015), presented the design of stacked E- and U-shaped patches to produce dual
band at 2.6 and 3.5 GHz with peak gain of 7.1 and 7.4 dBi. For designing a dual-band
circularly polarized slot antenna the U-shaped structure is presented. The antenna has a single
metallic layer and a coplanar waveguide (CPW) is used for feeding. U-strip slot and a U-slot
antenna have been designed for 2.6/3.6 and2.5/3.5 GHz bands application to evaluate the
performance of the versatile structure. To optimized some basic primary parameters of
proposed antennas a Differential Evolution (DE) algorithm is employed. For a given
operating frequency the axial-ratio bandwidths and optimum impedance can be achieved
without using the trial-and-error method. Prototypes of the two proposed designs were
constructed and studied experimentally.

Wang et al. (2015), illustrated the patch antenna design that is utilized for wireless
communications, the geometry is notches loaded that help in providing dual band at 1.45 and
2.35 GHz.

Guha and Kumar (2016), have demonstrated the comparison between dielectric resonator
and patch antenna using different feeding techniques. They designed the patch antenna on
circular geometry and resonator on solid cylinder.

Sabapathy et al. (2016), design patch antenna of Yagi Uda shaped with defected ground and
analysis the antenna performance by varying the parasitic elements. Further, W. -Q. Cao
demonstrated the antenna of mushroom-shaped on circular patch which is utilized for dual-
band operation. The operating frequency of proposed antenna is achieved at 4.42 GHz and
5.74 GHz. Thereafter, Salih and Sharawi designed compact U-shaped patch antenna on Roger
RO4350 dielectric substrate with defected ground plane and found that antenna resonates at
2.4 GHz and 5.2 GHz.

Shi et al. (2016), presented dual band patch antenna that resonates at two resonating
frequencies i.e., 2.5 and 3.5 GHz and these bands was achieved because of stacked patches
with angular slot.

Mathew et al. (2016), observed the designed patch antenna with V-shaped slot. The
proposed antenna resonates at i.e., 2, 3.5 and 5.6 GHz having gain of 4.4, 3.5 and 2.8 dBi
respectively (100). Studied a novel V slit stub and slot embedded circular microstrip antenna
with a single probe-fed having resonances in the three bands of UTMS. The antenna has
worldwide interoperability for microwave access (WiMAX and WLAN). The polarization is
linear in two bands and circular in one band in the UTMS. Observed asymmetrical V slits in
the patch boundary. The antenna introduces the perturbation necessary for circular
polarization. For that an embedded circular slot in the patch center are employed obtaining
three bands centered at 2, 3.5 and 5.6 GHz of 4.2, 2 and 6.2% impedance bandwidths
respectively. The axial ratio BW is 2.3% in the UMTS band. In the three bands 4.4, 3.5 and
2.8 dBi moderate gains are found. About 48% reduction is found in patch size comparing
with conventional patch antenna at fixed operating frequency. In WiMAX band the radiation
pattern is directional and in WLAN band omnidirectional. Thereafter, Zhu et al. presented the
U-shaped patch antenna for dual band operation. The two resonant frequencies 2.5 GHz and
5.8 GHz of gain 1.37 and 4.37 dBi respectively was observed.

K. Noguchi et al. (2016), proposed patch antenna of E-shaped using modal theory and
designed the equivalent circuit diagram further they have given the parametric analysis E-
shaped antenna theoretically. Thereafter, Liu et al. reported the dual band patch antenna of
ring shaped and analysed the designed antenna using cavity model.

Zhang et al. (2017), proposed a patch antenna of two U-shaped in such a manner that second
U-shape is inside the bigger U-shape. In this paper the study of low-profile dual-band
filtering antenna element is presented. The application of the antenna is for Long Term
Evolution (LTE) Multiple-input Multiple-output (MIMO) system for wireless customer
premise equipments (CPEs).