Continuously tunable substrate integrated waveguide bandpass filter in liquid crystal technology with magnetic biasing

A liquid crystal filled continuously tunable substrate integrated waveguide filter is proposed which has a high-quality (Q) factor. To measure the Q-factor, a single resonator measurement is performed by using magnetic biasing in a lab demonstrator for a proof of concept. The unloaded Q-factor is 102–105.6. The resonator is employed to create a three-pole Chebyshev filter with a centre frequency of 22 GHz and a bandwidth of 600 MHz. Measurement results show a 6 dB insertion loss with a return loss of about 10 dB. The filter is continuously tunable within a tuning range of 610 MHz.