Compact wide-passband and wide-stopband microstrip bandpass filter using multi-stub resonator

This paper presents a wideband microstrip bandpass filter with wide stopband. To achieve the wide stopband, a multi-stub resonator is introduced. The proposed resonator features high design freedom and can provide multiple transmission zeros for good near-passband selectivity and deep stopband rejection. The resonator is investigated via transmission-line model and a bandpass filter is fabricated to validate the design concept, which shows an improved F performance in comparison to previous works.