A compact, ultra-broadband coplanar-waveguide bandpass filter with good stopband rejection

A compact, ultra-broadband coplanar-waveguide (CPW) bandpass (BPF) filter is demonstrated. The proposed CPW BPF is designed essentially by exploiting the CPW short-stub and open-stub structures. Compared to the classical CPW BPF, the proposed filter is of a relatively simple and compact configuration. The demonstrated CPW BPF is of about 120% 3-dB fractional bandwidth, sharp selectivity, and great stopband rejection.