Design of a Miniaturized Split-Ring Resonator Based UWB Notched Bandpass Filter

—A compact selective ultra-wideband (UWB) bandpass filter primarily based on a multi-mode resonator is presented in this paper. A modified elliptical split-ring resonator (SRR) embedded in a variant of the ring resonator is employed to configure a microstrip UWB triple-notched bandpass filter with improved in-band and out-of-band filter properties. Further, the bent inter-digital coupled lines with apertures at the backside are applied to overall filter size miniaturization apart from contributing tight coupling through the entire structure. The three notches facilitated by the modified elliptic SRR have gained the ability to suppress the wireless local area network (WLAN) (5.48 GHz), C band RADAR (7.68 GHz), X band RADAR (8.82 GHz) interfering signals profoundly within the UWB. Simultaneously, the other filter attributes likely a uniform forward transmission coefficient with minimum attenuation (0.46 dB ∼ 1.52 dB), a high skirt factor (0.88), a wide passband (6.52 GHz) with high fractional bandwidth (FBW) (103.16%), broad upper stopband (3.47 GHz), etc. together establish the proposed filter, suitable for practical UWB applications. The uniqueness of this design lies in the flexibility to configure the filter as either a double-notched or a triple-notched bandpass filter by altering only the aspect ratios of elliptical SRR. Simulated filter characteristics are compared with the results obtained by measuring the fabricated prototype, and a good accordance between the compared outcomes validates the design pertinence well. © 2023, Electromagnetics Academy. All rights reserved.