Compact ultra-wideband bandpass filter using radial-stub loaded resonator

Conclusion In this paper, a UWB BPF has been investigated through quasi-equal allocation of the first three resonant frequencies of a radial-stub loaded resonator (RSLR) with aperture-backed parallelcoupled feed lines. The measured results validate the predicted design with good agreement, demonstrating that this proposed UWB BPF has very good in-band performance and steep skirt selectivity with a compact size.