A novel compact UWB BPF with independently controllable double notched bands and super wide upper stopband

Abstract

This paper presents a novel compact ultra-wideband bandpass filter without and with single or multiple notched bands with significant improvements in size reduction and upper stopband enhancement in comparison with its classical counterparts. A new multiple-mode resonator capable of producing multiple transmission zeros is exploited in the filter structure to produce notch bands and improve performance of the upper stopband. A parallel-coupled structure with tapped-line input/output is applied to significantly improve the selectivity and out-of-band rejection. The proposed filter achieves outstanding electrical performance, with wide passband from 2.93 to 10.64 GHz, two notched bands centered at 5.68 and 8 GHz with rejection level better than 40 dB, low insertion loss, high passband return loss, and wide stopband with suppression level better than −25 dB up to 30 GHz. These attractive features make the proposed filter a viable candidate for any number of broadband wireless communications and radar systems.