Reconfigurable Bandpass Filter With Separately Relocatable Passband Edge

A reconfigurable bandpass filter (BPF) with separately relocatable passband edges is demonstrated. The proposed design approach exploits simple stub-based structures and varactor-tuned microwave resonators for the BPF realization. The filter bandwidth reconfigurability is obtained via a separate relocation of each passband edge, and the harmonics inherited in the varactor-tuned microwave resonators are easily suppressed with the stub-based structures. The fabricated filter has a low passband insertion loss (<; 2.0 dB), a 21.8% higher band edge tuning range, a 18.2% lower band edge tuning range, as well as wideband suppression (>; 15 dB at the frequencies up to 5.5 GHz).