An Aperture-Backed H-Ring Ultra-Wideband Bandpass Filter with Floating Conductor for Spurious Suppression

作者：Kuek Albin Sui Hian^*; Su Hieng Tiong; Haldar Manas Kumar

来源：Electromagnetics, 2013, 33(6): 460-473.

DOI：10.1080/02726343.2013.799961

• dual symmetry
• ultra-wideband
• bandpass
• filter
• floating conductor
• aperture
• H-ring

This article presents analyses of and design procedures for a compact quintuple-resonance aperture-backed ultra-wideband bandpass filter. First, a one-wavelength H-ring resonated at 6.85-GHz center frequency is coupled with open stubs at both sides to produce a triple-resonance filter characteristic. To increase the resonances of the filter to five, stepped-impedance feed lines are then implemented to introduce two extra transmission poles at each side of the center frequency. The filter, which has a structure that is both horizontally and vertically symmetrical, simplifies the analysis to a quarter of the structure while enabling the stepped-impedance feed lines to be designed analytically. A wide aperture is then etched on the ground plane directly below each interdigital line to achieve strong coupling. This results in wider coupling gaps to enable in-house fabrication. A floating strip conductor is then added at the center of each ground aperture to suppress the spurious harmonic appearing at twice the fundamental frequency of the ring resonator. The filter is fabricated on an RT/Duroid 6010.2LM substrate (Rogers Corporation, Rogers, Connecticut, USA). The simulated and measured responses are in good agreement.

• 出版日期2013-8-18