Bandpass filter with tunable bandwidth using triple-mode H-type resonator

Abstract

A reconfigurable bandpass filter (BPF) with independently adjustable passband edges is demonstrated. The filter is formed by a H-type multi-mode resonator (MMR) loaded with varactor diodes. The equivalent even- and odd-mode circuits of the proposed varactor loaded MMR are analyzed. The bandwidth reconfigurability is achieved by using varactor diodes to individually relocate the even-mode resonant frequencies of the resonator. The measured results show the BPF has 23.7% and 26.4% tuning capabilities for the lower and upper passband edges.