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Dual band bandpass filter based on semi‐circular mushroom loaded substrate integrated waveguide
Author(s) -
Chaudhury Soumit Samadder,
Awasthi Seema,
Singh Rajat Kumar
Publication year - 2021
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.32720
Subject(s) - band pass filter , resonator , insertion loss , physics , bandwidth (computing) , passband , excited state , stopband , materials science , coupling (piping) , waveguide , optics , optoelectronics , telecommunications , engineering , atomic physics , metallurgy
This paper presents a dual band bandpass filter by loading two semi‐circular mushroom resonators (ScMRs) inside the cavity of a circular substrate integrated waveguide (SIW). TM 101 and TM 201 modes of the mushroom resonator loaded circular SIW cavity are excited to generate the first and second passbands respectively. As the proposed bandpass filter is based on circular SIW cavity, the passbands of the filter undergo relatively low insertion loss (IL) compared to other referred works. The selectivity is improved by generating four transmission zeros (TZs); two TZs are generated in between the two passbands by cross coupling the excited modes of the resonators and other two TZs are generated in lower and upper stopband by the source to load coupling. The passbands of the proposed filter are centred at 2.24 GHz and 4.35 GHz with 13% and 6.2% fractional bandwidth (FBW) respectively. A prototype of the proposed dual bandpass filter occupying a compact area of 0.3λ 0 × 0.3λ 0 is fabricated in Rogers RT/Duroid 5880. The measured minimum insertion losses for the first and second passbands are 0.9 dB and 1.1 dB respectively with a good agreement observed between simulated and measured results.