Synthesis Design of Chebyshev Wideband Band-Pass Filters With Independently Reconfigurable Lower Passband Edge

In this brief, a new and planar topology is presented for the synthesis design of Chebyshev wideband bandpass filters (WB BPFs) with independently reconfigurable lower passband edge. The proposed design is based on a new T-shaped resonator, whose topology and parameters can be directly derived from a 5th-order Chebyshev LC circuit. Then, a varactor is employed as the tuning element. By controlling the supplied voltage on the varactor, the lower passband edge of the proposed filter can be independently tunable in continue manners, while the upper one is maintained fixed. For verification, a reconfigurable prototype is designed and measured. As the measured and simulated results agree well with each other, a simple and high-efficiency design of reconfigurable-bandwidth WB BPFs is verified.