Design and Analysis of The Stub and Radial-Stub Loaded Resonator Band-Pass Filter with Cross-Shaped Coupled Feed-Lines for UWB Applications

In this paper, the procedure of attaining a compact microstrip ultra-wideband (UWB) band-pass filter (BPF) by the use of stub and radial stub loaded resonator and also cross-shaped coupled lines (CCLs) as feed-lines, is presented and discussed. Implementation of CCLs results in suppression of the unwanted pass-band harmonics while by loading the resonator, additional transmission zeros (TZs) are produced, which lead to improvement of the in-band performance of the BPF. Measurement results of the fabricated UWB BPF are in good agreement with simulation predictions and the presented BPF has a sharp rolloff and improved out-of-band performance in the frequency band of interest.