Defining the RF jamming system and

showing the importance and need of using it

in many places.

Giving a complete RF jamming system

design based on commercial of the shelf

circuit which can jam RF communication

signals transmitted by base stations in the

900MHz, 1800MHz and 2400MHz frequency

bands as three frequency bands used in

Saudi Arabia for mobile & wireless.

Implementation and testing the design by

using :

- Advanced Design System Software ADS.

- Available components (hardware).

If time permits, improving the project to

satisfy low cost and low power consumption.

Design Methodology

Tri-Band RF Jamming SystemTeam: Sadeq AlKhalifah – Mohammad AL-Khulaif – Ali Al-Turaifi

Advisor: Dr. Oualid Hammi

The designed RF jammer consists of mainly two

parts: a low frequency noise generator, and an

RF front end. The noise source generates a low

frequency random noise. In the RF front end

part, the noise signal is amplified and up-

converted to each of the three frequency bands

which they 900MHz, 1800MHz and 2.4 GHz. The

three noise signals centered in the middle of the

targeted frequency bands are then combined

and sent through a multi-band antenna.

Objectives Noise Generator

ADS Simulation

Introduction

Radio frequency (RF) Jamming System

refer to a set of radio frequency

equipments that produce a RF signal to

disturb a targeted communication and

prevent it from being established. This can

be applied for instance for cell phone or

other wireless applications. Jamming

results in blocking the signal from the

receiver point view that would be no

service to cell phone and wireless

networks within the effective radius of the

jammer.

Cell phones work by communicating with a

service network through the utilization of

cellular towers or base stations. In Saudi

Arabia, wireless communication providers

use the 900 MHz and 1800 MHz frequency

bands for mobile communications, where

as (Wi-Fi) signals are in the 2400MHz

frequency band. These three bans are the

targeted ones.

Conclusion

Future Work

Advanced Design System (ADS) is the used

software in this project. The simulation

schematic is presented for the 900 MHz, and

for the two band which are 1800MHz and

2.4GHz. The noise source was replaced by a

single-tone (continuous wave) generator

providing a signal at the center frequency of

the noise source’s output signal and with the

same power level (-75 dBm). The various

components of the front-end (such as

amplifiers, mixers, combiners, etc…) were

simulated using their parameters available in

the datasheet.

Noise generator is based on the noise generated

by the Zener breakdown phenomenon. The circuit

of the noise generator where the zener diode is

reversely connected to 14V-DC source from one

terminal and the other terminal is connected to a

100 kΩ resistor and a 720 pF capacitor where the

output is taken from. After constructing the noise

circuit and measuring its spectrum using a

spectrum analyzer, it was found that it has a

bandwidth of almost 60MHz centered at

approximately 50MHz with a power of -75dBm.

The Tri-Band RF Jamming System that can jam

RF GSM signals at 900 MHz and 1800 MHZ, and

Wi-Fi signal at frequency 2.4 GHz can be

designed based on commercial of-the-shelf

components.. This system can be achieved by

building a noise generator produces noise with

low frequency and a known power level. Then

to amplify this noise to an amount of power

more than the power of the aimed signals and

up-converted to their frequency and

transmitted using an antenna.

The design should be improved by adding more

applicable amplifiers to reach a higher power

levels that enables the system to increase its

coverage area, because the further the noise

signal from the antenna the weaker it became

due to the high loss of air.

RF Front-End

Amplification stage:

In this stage four amplifiers of the Two types of

ZFL-1000LN+ and the ZX60-3018G+ were used,

each has a gain of 23 dB and 22 dB respectively

which result in a gain of around 90 dB in low

frequency.

Frequency up-conversion

The up-converting was done in two stages. In the

first stage, the amplified noise signal obtained at

the output of the amplification stage is

modulated to the center frequency of 920MHz. In

the second stage, takes the amplified and

modulated noise generated at the output of the

first up-conversion stage is fed into a 3-way

splitter.

One of the splitter outputs represents the noise

signal that is ready for transmission in the 900

MHz band. The remaining two signals are

modulated to their targeted carrier frequencies

(1.8 GHz and 2.4 GHz). The three RF signals are

then combined and fed to the antenna for

transmitting. Testing

The tests and power measurements were done

using a computerized spectrum analyzer (EXA

Signal Analyzer N901A) . These measurements

were taken at four stages: before and after the

amplification stage, and right after each up-

converting stages. Then, the readings have

been compared to the estimated ones by the

ADS. Finally, the project has successfully

jammed the three targeted bands.