Compact Dual-Wideband Bandpass Filter Using a Novel Penta-Mode Resonator (PMR)

A novel dual-wideband bandpass filter (BPF) with controllable center frequencies and bandwidths, as well as high band-to-band isolation level and skirt selectivity, is presented in this letter. The proposed filter is based on a novel penta-mode resonator (PMR). The first two modes are employed to generate the first passband, and the other three modes are used to form the second one. Even- and odd-mode analysis is applied to analyze the proposed resonator. By changing the dimension parameters, the center frequency and bandwidth of each passband can be tuned. Meanwhile, four transmission zeros are created due to the transversal signal interference between the two input-to-output signal paths and the use of a dual-finger feed structure. The measured and simulated results are in good agreement.