Vol. 97

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2021-03-29

Compact Quarter Mode and Eighth Mode Substrate Integrated Waveguide Bandpass Filters with Frequency-Dependent Coupling

By Zhiwei Shi, Guohui Li, Yulu Song, and Binbin Cheng
Progress In Electromagnetics Research Letters, Vol. 97, 51-59, 2021
doi:10.2528/PIERL21012201

Abstract

This paper presents two size-miniaturized quarter mode (QM) and eighth mode (EM) substrate integrated waveguide (SIW) bandpass filters (BPFs), which are embedded with a novel frequency-dependent coupling (FDC) structure. The proposed FDC is implemented as a composition of balanced folding lines and inductive iris. One additional transmission zero (TZ) introduced by FDC between two cavities leads to higher frequency selectivity and better out-of-band rejection. Higher order modes suppression appears by combining the loaded paired open stubs on feeder lines with FDC technique, achieving a wide stopband. Meanwhile, the circuit dimension is further reduced by symmetrically cutting SIW. To validate the novel approach, the frequency-dependent coupling matrix (CM) is implemented to determine characteristics of the proposed structure in theory, QM- and EM-SIW BPFs loaded with FDC have been designed, fabricated and measured. Experimental results illustrate the characteristics of miniaturization and good performance. All results are in good agreement.

Citation


Zhiwei Shi, Guohui Li, Yulu Song, and Binbin Cheng, "Compact Quarter Mode and Eighth Mode Substrate Integrated Waveguide Bandpass Filters with Frequency-Dependent Coupling," Progress In Electromagnetics Research Letters, Vol. 97, 51-59, 2021.
doi:10.2528/PIERL21012201
http://www.jpier.org/PIERL/pier.php?paper=21012201

References