Design and Analytical Studies of Signal Jammer

BACHELOR OF TECHNOLOGY
in
ELECTRONICS AND COMMUNICATION ENGINEERING
Submitted by
Shikhar Adelphi (Roll No. 218414)
Aditya Sinha (Roll No. 218412)
Amita (Roll No. 218403)
Romesh Pushkar (Roll No. 218411)

Under the Supervision of

Dr. Anuradha Sonker
(Assistant Professor)

Department of Electronics and Communication Engineering

University Institute of Engineering and Technology
Babasaheb Bhimrao Ambedkar University
(A Central University)
Lucknow – 226025
December,2024

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 CANDIDATE'S DECLARATION

We hereby declare that this submission is our own work and, to the best of our
knowledge and belief, it contains no material previously published or written by
any other person, nor any material that has been substantially accepted for the
award of any other degree or diploma by any university or institution of higher
learning, except where due acknowledgment has been made in the text.

(Signature) (Signature)
Shikhar Adelphi Aditya Sinha
Roll No. 218414 Roll No. 218412
Department of Electronics and Department of Electronics and
Communication Engineering Communication Engineering

(Signature) (Signature)
Amita Romesh Pushkar
Roll No. 218403 Roll No. 218411
Department of Electronics and Department of Electronics and
Communication Engineering Communication Engineering

Date: 29/11/2024

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 CERTIFICATE

This is to certify that Shikhar Adelphi, Amita, Aditya Sinha,

and Romesh Pushkar have successfully carried out the work
presented in this minor project report titled "Design and Simulation of
a Signal Jammer" in partial fulfilment of the requirements for the
award of the Bachelor of Technology degree from Babasaheb
Bhimrao Ambedkar University, Lucknow, under my supervision. The
project report represents the result of original work and research
conducted by the students themselves, and the contents of this report
have not been used as the basis for the award of any other degree to
the candidates or to any other individual.

Date: 29/11/2024
Place:

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 ACKNOWLEDGEMENT

It has been an honor and privilege to have Dr. Anuradha Sonker as

our supervisor during our Bachelor of Technology (B.Tech) program.
We would like to express our sincere gratitude to her. Her vast
technical knowledge and insights have provided an excellent
foundation in this field. Her enthusiasm, encouragement, and faith in
us have inspired a true passion for this work and helped us persevere
through the setbacks encountered along the way. We feel fortunate
and proud to have worked under her supervision.
We express our deep gratitude to Dr. Balraj Singh, Head of the
Department of Electronics and Communication Engineering, for his
kind support and encouragement throughout the course of this project.
We also acknowledge the support of Prof. Shishir Kumar, Director,
UIET, Babasaheb Bhimrao Ambedkar University, Lucknow, for his
assistance and encouragement during the development of this project.

Shikhar Adelphi
Aditya Sinha
Amita
Romesh Pushkar

Department of Electronics and Communication Engineering

University Institute of Engineering & Technology
Babasaheb Bhimrao Ambedkar University, Lucknow, 226025

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 Abstract

This project focuses on the design and simulation of a signal jammer,

incorporating a noise generator circuit and antenna system. The noise
generator was designed using Multisim by National Instruments
(NI), where the output of the jammer circuit was simulated to
generate noise signals. The overall performance of the signal jammer
setup, including the transmission of the noise signal, was further
simulated using MATLAB Simulink. The jammer is coupled with a
monopole antenna, which was designed and simulated using CST
Studio Suite.
The goal of the project is to develop a portable jammer capable of
disrupting communication signals in a specified frequency range. The
design is based on a wideband RF signal jammer that can be tailored
to target specific frequencies by adjusting key components like
inductance, capacitance, and power output.
The study includes several key calculations and analyses, including
the gain of the antenna, the distance covered by the jammer, and
the frequency generated by the noise generator circuit. The
performance of the jammer was evaluated in terms of its signal
interference, with a specific focus on the generated noise frequency
and its ability to disrupt communication systems. The noise signal
generated was found to operate effectively within the desired
frequency range.
In addition to its application in electronic warfare, this signal jammer
can be utilized in anti-cheat measures for examinations, where it
can disrupt unauthorized communication devices. The results also
have potential use in improving communication security by blocking
or jamming specific frequencies. The findings provide valuable
insights into the practical design and application of noise-based
jamming systems, helping to optimize such systems for both defense
and civilian applications.

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 Table of contents
Chapter No. Page No.
Chapter 1- Introduction……………………………………..7
1.1 Introduction to Signal Jamming…………………...7
1.2 Principle of Operation…………………………......8
1.3 Motivation…………………………………………9
Chapter 2- Literature Survey………………………………10
2.1 Background of Jammer…………………………..10
2.1.1 Types of Jamming Techniques…………………...11
2.1.2 Concept of Noise…………………………………12
2.2 Narrowband Jammer ……………………………..13
2.3 Block Diagram and Working …………………….15
2.3.1 Component Selection and Construction………….16
2.3.2 Schematic Diagram……………………………….17
2.3.3 Layout of Noise Generator………………………..17
2.3.4 Monopole Antenna………………………………..18
2.4 Applications of project model…………………….18
Chapter 3- Analysis and Observations………………………19
3.1 Output from Multisim Simulation………………...19
3.2 Output from Simulink Simulation…………………20
3.3 Calculations………………………………………..22

Chapter 4- Conclusions and Future scope of work….……..25

References…………………………..…………………………..26

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CHAPTER 1-INTRODUCTION

1.1 Introduction to Jamming

Communication is one of the necessities for human beings to live
connected in this vast world. The traces of communication are first
found in the ancient Persian kingdom where fire is used to
communicate between distant places, it is followed by communication
ways like pigeon post, and traditional postal service, followed by
wired communication like telegram and telephone, and finally the
introduction of wireless communications. With the introduction of
wireless communication, there came the introduction of mobile
phones which changed the world into a global village where distance
is no matter an obstacle to communication. Nowadays every
communication device is either directly or indirectly using wireless
communication. Jammers work by outputting an RF signal at the
same frequency expected by the device that’s being jammed, but at a
higher power compared to the normal signal. The jamming signal
itself is usually random noise or a pure signal. The device being
jammed will then receive the higher power signal which is from the
jammer, and then the devices can no longer function correctly. The
jamming signal itself is usually random noise or a pure signal.

A Signal Jammer is an electronic device which used to fail or disturb

any communication system.
Signal Jammer produces a noise frequency range similar to the
communication frequency range which tend to add the noise to the
communication frequency. A signal jammer interferes with or blocks
the transmission of radio signals, essentially disrupting
communications. Jammers can target a variety of communication
systems, such as:

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 1. Cell phones: Disrupting cellular signals, preventing calls or text
messages.
2. Wi-Fi: Interrupting wireless internet connections.
3. GPS: Blocking or distorting GPS signals, making navigation
systems unreliable.
4. Radio communications: Disrupting radio frequencies used by
emergency services or other radio-based systems.
5. Bluetooth: Interfering with short-range wireless devices like
speakers, headsets, or keyboards.
Signal jammers are often used in environments where control over
communications is necessary, such as in military operations, security
settings, or during certain law enforcement activities.

1.2 Principle of Operation

A Signal Jammer works by emitting radio frequency signals that
overpower or scramble the signals of other electronic devices,
preventing them from working properly.
Mobile phone communication typically operates within a specific
range of frequencies. When noise or interference is introduced within
this frequency range, it can disrupt or block the communication,
causing mobile services to fail or become unstable.
 Thus, Signal Jammer is a device that generates interference by
adding noise to the same frequency range used by mobile
communication.
 For example, if certain applications are operating on the 930
MHz frequency range, and noise within this range is introduced,
those applications may malfunction or fail to work properly.

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FIG 1A. Concept of jamming

1.3 Motivation
In today’s world, wireless communication has become an integral part
of daily life, but it also poses significant challenges in terms of
security, privacy, and misuse. The need to safeguard sensitive areas,
prevent unauthorized communication, and ensure confidentiality has
never been more crucial. Signal jammers play a vital role in
addressing these concerns by disrupting communication channels
effectively. Whether it's maintaining discipline in examination halls,
protecting high-security zones, or ensuring safety during critical
military operations, signal jammers serve as a powerful tool. This
project is driven by the motivation to understand and design a signal
jammer that not only prevents misuse of wireless technology but also
enhances security in critical environments, contributing to a safer and
more controlled communication ecosystem.

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CHAPTER 2- LITERATURE REVIEW

2.1 Background of Jammer

The concept of Signal jamming traces its roots to the early 20th
century, following the invention of radio communication
by Guglielmo Marconi in 1895. Marconi’s work on wireless
telegraphy marked the first use of radio waves for communication. As
radio technology became widely adopted, interference—whether
accidental or intentional—began to be recognized as a potential threat
to reliable communication.
The first deliberate efforts to jam signals can be traced to World War
I (1914–1918), where early military forces used basic methods to
disrupt enemy radio transmissions. This included broadcasting static
or white noise on the same frequency to render the communication
unintelligible.
During World War II, signal jamming became a critical aspect of
electronic warfare. Military forces developed more sophisticated
jammers to counter enemy radar and radio systems. For instance, the
Allies employed "Window," a radar-jamming method using aluminum
strips to confuse enemy radar to suppress foreign broadcasts which
were seen as tools of propaganda.

FIG 2A. Iron Curtain, Russia

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2.1.1 Types of Jamming Techniques
Barrage Jamming
In Barrage Jamming, a wide range of frequencies, including all the
cellular communication bands, are jammed simultaneously using
high-power signals.
Random jammer
A Random jammer intermittently transmits either random bits or
regular packets into networks. Contrary to the above two jammers, it
aims at saving energy. It continuously switches between two states:
sleep phase and jamming phase. It sleeps for a certain time of period
and then becomes active for jamming before returning back to a sleep
state.
Spot Jamming
This technique focuses on jamming a specific frequency band (e.g.,
GSM 900 MHz, 1800 MHz, or LTE). It prevents communication only
within the targeted band while leaving others unaffected.
Reactive jammer
Reactive jammer starts jamming only when it observes a network
activity occurs on a certain channel. As a result, a reactive jammer
targets on compromising the reception of a message. It can disrupt
both small and large sized packets. Since it has to constantly monitor
the network, reactive jammer is less energy efficient than random
jammer.
Pulsed-noise jammer
Pulsed-noise Jammer can switch channels and jam on different
bandwidths at different periods of time. Similar to the random
jammer, pulsed-noise jammer can also save energy by turning off and
on according to the schedule it is programmed for.
Uplink and Downlink Jamming

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Uplink jamming targets the uplink frequency i.e communication from
the mobile phone to the base station. It blocks the phone’s ability to
send data to the network, resulting in failed calls and data services.
While Downlink Jamming jams the downlink frequency
(communication from the base station to the mobile

2.1.2 Concept of Noise

Noise refers to any unwanted or random variation in a signal that
interferes with its clarity and quality. Noise can distort or mask the
information being transmitted, leading to errors in communication or
processing. Noise affects communication systems by reducing
the Signal-to-Noise Ratio (SNR), which is the ratio of the signal
power to the noise power. A lower SNR means the signal becomes
less distinguishable from noise, leading to errors in data transmission
and reception. Mathematically, Noise is represented as an additive
component to the signal:
y(t)= s(t)+n(t)
Where: y(t) is the received signal.
 s(t) is the original signal.
 n(t) is the noise component.

FIG 2B. Effect of Noise signal on Message signal.

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2.2 Narrowband Jammers
A Narrowband Jammer is a jamming device designed to interfere
with a specific frequency or a narrow range of frequencies used by a
target communication system. It introduces noise or an interfering
signal directly onto the operating frequency of the device, such as the
mobile phones transmission or reception band.
In this project, we have designed a narrowband signal jammer
circuit using Multisim. The primary objective of the circuit is to
generate noise to disrupt mobile communication in a targeted
frequency range. The jammer works by amplifying a noise signal and
injecting it into the communication frequency, thereby lowering the
Signal-to-Noise Ratio (SNR) and causing interference in the mobile
system

2.3 Block Diagram and Working

The Signal Jammer circuit is mainly made up of three circuits:
1. RF Amplifier
2. Tuned oscillator
3. Noise producing capacitors

 RF Amplifier
RF Amplifier is made up of capacitors, transistor and resistor. It is
used to amplify the signal and noise signal produced by the noise
producing capacitors.
In our circuit we have chosen two capacitors, one of 102pF and 103Pf
parallel to a 39k resistor and also placed 1uF capacitor to the Base of
transistor. This constitutes our RF Amplifier circuit.

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  Tuned oscillator
Tuned oscillator produces high frequency with less damping. In this
circuit we have taken a 22nH Inductor and a 15pF Capacitor parallel
to each other. This arrangement forms a tuned oscillator circuit which
produces very High frequency with minimum damping.
 Noise producing capacitors
Noise producing capacitors produces the noise signal which will get
added in communication frequency range. Here we have an
arrangement of two 4.7pF capacitors parallel to each other at the
Right side of Transistor.

FIG 2C: Block Diagram of Jammer

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Working
The Power Supply provides the necessary energy for the operation of
the entire circuit. In this design, a 4V DC power source is used to
power all components, including the transistor, resistor, inductors and
capacitors. The Tuned Oscillator is the first block responsible for
generating the signal that will be used for jamming. It constitutes a
22nH inductor (L) and a 15pF capacitor (C), which are connected in
parallel to form an LC circuit. The inductor stores energy in its
magnetic field, while the capacitor stores energy in its electric field.
As the current flows through the LC circuit, the capacitor charges and
discharges, creating a continuous oscillation. Current from the power
supply flows into the capacitor, causing it to charge. As the capacitor
charges, it stores energy in the form of an electric field between its
plates. Once the capacitor is fully charged, it starts to discharge. The
stored energy is released back into the circuit, and the capacitor's
voltage decreases. This charging and discharging cycle happens
repeatedly, creating an oscillation or alternating current (AC) signal.
The inductor (22nH) is responsible for creating a magnetic field when
current flows through it. When current starts flowing through the
circuit, the inductor resists the rapid change in current (this is
called inductive reactance). This creates a magnetic field around the
inductor. As the capacitor discharges and the current increases, the
inductor stores energy in its magnetic field. When the capacitor begins
charging again, the magnetic field in the inductor collapses, and the
energy stored in the inductor's magnetic field is transferred back to the
capacitor, helping it recharge. The combination of these two
components creates a high-frequency signal that is used for jamming.
The RF Amplifier block is designed to amplify the high-frequency
signal generated by the tuned oscillator. It consists of an NPN
transistor (2N3707), capacitors (102pF, 103pF, 1uF), and a resistor
(39kΩ). The transistor amplifies the signal, which is necessary for
producing a stronger output that can interfere with the mobile
communication system. Two 4.7pF capacitors are connected in

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parallel with each other. These capacitors don’t just store and release
energy like typical capacitors in a power supply circuit. Instead, they
are chosen and connected in a way that helps produce random noise at
high frequencies. Capacitors can store and release energy quickly,
which allows them to create rapid fluctuations in voltage that
contribute to random noise. This noise is injected into the signal at the
output of the circuit. The output from the noise-producing capacitors
is fed into the monopole antenna. The antenna acts as a transducer
that converts the high-frequency electrical signal into electromagnetic
waves.

2.3.1 List of Components

Item No. Component Name Value/Specification
1 NPN Transistor 2N3707
2 Inductor 22nH
3 Capacitor 15pF
4 Resistor 100Ω
5 Resistor 39kΩ
6 Capacitor 102pF
7 Capacitor 103pF
8 Capacitor 1µF
9 Capacitor 4.7pF
10 Capacitor 2.2pF
11 Power Supply 12V
12 Monopole Antenna 1.17165dBi

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2.3.2 Schematic Diagram

FIG 2D: Schematic of Noise generator

The figure above shows the schematic diagram of our Signal jammer, which has
been designed on MultiSim by National Instruments.

2.3.3 Layout of Signal Jammer PCB

FIG 2E: PCB Layout of Signal jammer on PCB Wizard

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2.3.4 Monopole Antenna

FIG 2F: Monopole Antenna

The monopole antenna has been designed in CST studio suite having a length of
3 cm, optimized to operate efficiently at the desired frequency, providing a
suitable radiation pattern for signal transmission in the jammer circuit.

2.4 Applications of project model

1. Mobile Phone Jamming in Exam Halls:
 The compact, PCB-based jammer can be installed in a grid
formation within exam halls to prevent mobile phones from
disrupting the exam environment by blocking signals in the
surrounding area.
2. Libraries:
 A small jammer chip can be placed in strategic locations across
libraries to block mobile signals, ensuring a quiet, distraction-free
environment for studying and reading.
3. Offices and Meetings:
 The device can be discreetly installed in office buildings, ensuring
that mobile phones do not interfere with sensitive discussions,
confidential meetings, or data security.

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CHAPTER 3- Analysis and Observations

3.1 Output from Multisim Simulation

We have simulated our circuit design on MultiSim on multiple values of LC
Tuning circuit to observe changes in the Frequency.
CASE 1: L=22×10nH, C=15×10^pF

FIG 4A: Observed waveform No.1

Case 2: L=5nH, C=1.566pF

FIG 4B: Observed waveform No.2

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 Observation
It has been observed that by reducing the values of L and C, we can achieve
higher frequencies.

3.2 Output from Simulink Simulation

FIG 4D: Block diagram

We have designed the Block diagram of jamming process as seen earlier in FIG
1A. on Simulink by MATLAB. Here, different Blocks represent different
Sections in our Model.
The Sine Wave model represents the Target device to be Jammed. Here, we
have assumed the target is a Mobile phone in vicinity of Jammer. The Band-
Limited White Noise represents the Signal Jammer device. The Gain block
represents the Monopole antenna that provides additional Gain to the signal
generated. Finally, we have connected a Spectrum Analyzer to Observe the
effect of Jamming.

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FIG 4F: Effect of Jamming observed

Monopole Radiation Pattern

FIG 4G: Radiation pattern of Monopole antenna

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3.3 Calculations
1. For the calculation of Resonant frequency generated by the LC Tuning
circuit, we know that

Thus, putting the values of L and C:

Case 1:
 L=22×10^−9H (22 nH)
 C=15×10^−12 F (15 pF)
F= 277.6 MHz
Since this frequency is too low to make interferences, we take more cases.
Case 2:
 L=10×10^−9H (10 nH)
 C=2.53×10^−12 F (2.53 pF)
F= 1 Ghz
Case 3:
 L=5×10^−9H (22 nH)
 C=31.6×10^−12 F (15 pF)
F= 1.8Ghz
This is the frequency we will input to the frequency transmitted by Target
device to produce jamming.
2. Calculation of gain of the monopole
Given,
Total Efficiency: -0.2709 dB
 Directivity: 1.137 dBi
 Radiation Efficiency: 0.03585 dB
 Frequency: 1.8 GHz (as given)
The formula to calculate the gain is:

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G=D⋅Efficiency
Where:
 Directivity D is given in dBi
 Efficiency is the radiation efficiency
The gain can be calculated using the relation:
Gain (dBi)=Directivity (dBi)+Radiation Efficiency (dB)
Gain=1.17285dBi
3. Calculation of power radiated from the monopole antenna
The input power to the antenna is determined by the voltage supplied
and the impedance Z of the antenna using the formula:
Pi=V^2/Z
Where:
 V=4 V (given),
 Z=50 Ω (assumed for a standard antenna impedance).
Substituting the values:
Pi=0.32W
4. Calculation of Power radiated out
The radiated power emitted by the monopole antenna is calculated by:
P(radiated)=P(input)×Gain
Prad=0.43 W

5. Calculation of Distance covered by jammer

To calculate the distance covered by jammer, we have used the Cost-231
Model:
Given:
 Frequency f=1800 MHz (1.8 GHz),
 Transmitting antenna height=2m,
 Receiving antenna height=1.5m,

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  Transmitted power=0.43W,
 Received power =1 μW=10^−6
First, we Calculate Path Loss
L(dB)=10log10(Preceived/Ptransmitted)
It is calculated as 56.32dB
Then Receiver Height Correction
a(hrx)=(1.1log10(f)−0.7)hrx−(1.56log10(f)−0.8)
which is calculated as 0.0428m
Now applying the Cost-231 Model Formula
LdB=46.3+33.9log10(f)−13.82log10(htx)−a(hrx)+(44.9−6.55log10(htx))log10
(d)
On Substituting the values, the distance covered by jammer is 5.7m

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Chapter 4- Conclusions and Future scope of work

Conclusion
The design and implementation of the signal jammer PCB were completed
successfully, achieving the intended functionality of disrupting mobile phone
communication signals within the target frequency range. The project combined
theoretical analysis, simulation, and practical design to develop a compact,
efficient jammer capable of generating noise at 0.4 GHz to interfere with signals
at 1.8 GHz.
Throughout the process, various challenges such as signal attenuation and
precise frequency generation were addressed through iterative testing and
optimization. The final design, validated through simulations and hardware
testing, demonstrated stable performance with effective signal radiation
supported by the monopole antenna's gain. The PCB layout was optimized to
ensure minimal internal interference, reliable operation, and compliance with
project specifications.
In conclusion, the project successfully met its objectives, showcasing the
feasibility of a portable and functional signal jammer for controlled
applications.

Future Scope
In the future, the model can be enhanced by incorporating band-pass filtering to
selectively allow communication within specific frequency ranges. This feature
would enable the jammer to block unauthorized signals while permitting
essential communication devices, such as those used by invigilators during
exams, to operate without interference.
By integrating band-pass filters, the system can provide a more controlled
jamming environment, ensuring that critical communication channels remain
unaffected while unauthorized devices are restricted. This improvement would
significantly increase the practicality and versatility of the jammer in real-world
applications, especially in scenarios requiring selective signal blocking.

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References

Microwave Engineering" by David M. Pozar

Interference Techniques in Wireless Communications: A Review" by P. Gupta

and A. K. Sharma

Jamming in Wireless Networks: Analysis and Countermeasures" by R. T.

Kennedy et al

Design and Analysis of Portable Signal Jamming Devices" by S. Kumar et al.

Images from
https://scholarworks.montana.edu/server/api/core/bitstreams/b1d9de32-0aa5-
4aa9-b6e1-9dde2aee188c/content

https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/
Chemometrics_Using_R_%28Harvey%29/10%3A_Cleaning_Up_Data/
10.1%3A_Signals_and_Noise

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