Wide upper-stopband super-UWB BPF based on SCRLH transmission line structure

A super-ultra-wideband (UWB) bandpass filter (BPF) with fractional bandwidth of 138% and wide upper stopband is proposed based on a simplified composite right/left-handed transmission line (SCRLH TL) structure. The non-uniform periodical structure can help the SCRLH TL to realise a wider passband, while the complementary split-ring resonators are etched in the ground plane to achieve better performance of the upper stopband. In addition, the slots carved around the via make it feasible to reduce the overall size. The super-UWB BPF has been designed, fabricated and measured. Good agreement is shown between measurement and simulation.