An Ultra-Broadband Coplanar-Waveguide Bandpass Filter With Sharp Skirt Selectivity

An ultra-broadband coplanar-waveguide (CPW) bandpass filter (BPF) is demonstrated. The proposed CPW BPF is designed via cascading CPW lowpass and bandpass structures. As compared to the classical CPW BPFs, the ultra broadband is realized relatively easily by separately adjusting the cutoff frequencies of the CPW lowpass and bandpass structures. The cascaded CPW BPF is of greater than 120% 3-dB fractional bandwidth, very sharp skirt selectivity, good stopband rejection, and no repeated passbands