 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 System Team: 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. ObjectivesNoise 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 ZX G+ 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.