Design of compact microstrip bandpass filter with two switchable operating passbands

Abstract

A new bandpass filter (BPF) with two switchable operating passbands has been proposed. The BPF topology is formed by switchable resonators and stepped-impedance resonators. The two operating bands can be switched on and off independently. For verification, a switchable BPF with a third-order Chebyshev bandpass response was designed and fabricated using microstrip technology. The developed BPF was measured to verify the predicted and simulated results. A close agreement was observed between them. The proposed switchable BPF has good in-band and out-of-band performances. Besides, the attenuation is > 30 dB as the passband is switched off.