A dual mode circular waveguide cavity resonator based frequency tunable band pass filter using a single tuning element

Abstract

In this letter, we present a tunable band pass filter (BPF) using a dual-mode circular waveguide cavity resonator using a single tuning element. For the proof of the concept, a 2nd order tunable BPF has been designed and developed over a tuning range from 4.92 to 6.1 GHz (21.4%). The measured bandwidth is 85 ± 10 MHz over the entire tuning range. The peak insertion loss is within 1.3 dB and return loss is better than 15 dB. The tunable filter is proposed to be used in high Q reconfigurable radio systems.