Design of a novel stub loaded asymmetric rectangular ring resonator based ultra-wide notched-band bandpass filter

Abstract

This paper establishes a novel method to generate an ultra-wideband (UWB) bandpass filter (BPF) with four notches. Initially, this method employs a stub-loaded rectangular ring resonator (SLRRR) based compact structure to develop a UWB bandpass filter. Upgradation of the SLRRR structure into a stub-loaded asymmetric rectangular ring resonator (SLARRR) based structure in the next move facilitates the prospective filter with four notches at 4.34 GHz (S-band radar), 5.48 GHz (WLAN), 6 GHz (Wi-Fi 6E), and 9.3 GHz (X band radar) respectively possessing high rejection ability. This compact-sized (1.14λg × 0.29λg) proposed filter is characterized by a wide passband extending from 3.3 to 10.84 GHz with low insertion loss of <−0.69 dB, good selectivity of 0.8, and a 4.6 GHz wide upper stopband with −20 dB high rejection level. Structures are fabricated, measured, and compared with the obtained simulation outcomes. The resemblance between the compared results corroborates the applicability of such compact structure.