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

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 10.64GHz, two notched bands centered at 5.68 and 8GHz with rejection level better than 40dB, low insertion loss, high passband return loss, and wide stopband with suppression level better than 25dB up to 30GHz. These attractive features make the proposed filter a viable candidate for any number of broadband wireless communications and radar systems.