5-GHz-band center frequency and bandwidth tunable dual-band bandpass filter

This paper proposes a novel tunable dual-band bandpass filter that can individually tune its center frequency and the bandwidth of its two passbands. The proposed filter comprises two tunable single-band filters and branch lines that achieve a nearly independent tuning capability of its center frequency and the bandwidth in each passband. In addition, when tuning the frequency characteristics of one passband the characteristics of the other passband are not significantly affected. To the best knowledge of the authors, this is the first dual-band bandpass filter with highly flexible tuning capabilities in the 5-GHz band.