Lumped-Element Based Tunable Bandstop Filter for Airborne UHF Communication System

Airborne tactical communication systems are facing a significant issue with RF co-site interference caused by various factors such as jamming, nearby radio stations, or co-located RF systems on the same aircraft. This interference can cause the receiver's front-end amplifier to compress and distort, which can mask weaker signals of interest. The frequency of interferer signals can also vary over time, making it challenging to address the problem. However, the paper presents a potential solution in the form of a tunable lumped-element based band-stop filter for UHF-band radio systems. The filter's tunable range spans from 225 MHz to 400 MHz and can provide a rejection bandwidth of 2.5 MHz to 4 MHz, which can be controlled by adjusting the scaling capacitor and resonant capacitor values. This proposed topology offers greater flexibility in terms of frequency and bandwidth control, making it more adaptable to changing interference frequencies over time. Overall, this paper presents a promising solution to the issue of RF co-site interference faced by airborne tactical communication systems.