Research on a novel microstrip UWB notch-band BPF

A novel microstrip UWB notch-band BPF is presented which has good out-of-band performance using hybrid microstrip/coplanar waveguide (CPW) structure. The proposed filter is comprised of a CPW open-end resonator and two short-circuited resonators whose performance has showed by simulation and experiment respectively. Measured results demonstrated the UWB properties from 3.4 to 9.1 GHz (-3 dB bandwidth), which is fractional bandwidth of 92% at the center frequency 6.2 GHz and the notch band can be changed optionally by adjustment of mismatch of the two resonators. In addition, the filter exhibits good out-of-band performance by the adoption of a short stub-loaded resonator.