Design and implementation of an intrinsically-switched 22–43 GHz tunable bandstop filter

A 22-43 GHz tunable bandstop filter is presented, with relevant background theory, design methodology explained. The filter employs silicon-micromachined evanescent-mode cavity resonators, tuned by low-power electrostatic actuators. Low passband of insertion loss of less than 2 dB is obtained, and high stopband attenuation of over 60 dB is achieved by using quasi-absorptive filter design principles. Further reconfigurability is added by utilizing intrinsically-switched coupling elements, which allow the bandstop filter to achieve an all-pass response when the resonators are tuned to a certain frequency.