Open AccessBalanced substrate integrated waveguide bandpass filter with high selectivity and common‐mode suppression
Author(s) -
Chu Hui,
Li Peng,
Chen JianXin
Publication year - 2015
Publication title -
iet microwaves, antennas and propagation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.555
H-Index - 69
eISSN - 1751-8733
pISSN - 1751-8725
DOI - 10.1049/iet-map.2013.0708
Subject(s) - passband , band pass filter , coupling (piping) , substrate (aquarium) , filter (signal processing) , selectivity , transmission (telecommunications) , mode (computer interface) , waveguide , materials science , common mode signal , electronic engineering , differential (mechanical device) , topology (electrical circuits) , physics , optics , optoelectronics , computer science , engineering , chemistry , telecommunications , electrical engineering , oceanography , operating system , biochemistry , metallurgy , catalysis , geology , analog signal , thermodynamics
A new method of designing balanced (differential) bandpass filters (BPFs) with high selectivity and common‐mode suppression is proposed and implemented by taking advantage of the existence of multiple substrate integrated waveguide cavity modes. The major design concept is by properly choosing, feeding and coupling dual‐mode cavities operating at TE 102 and TE 201 modes so as to not only provide capabilities to realise the desired differential‐mode passband associated with two transmission zeros, but also generate high common‐mode suppression over a wide range. Two X‐band BPFs with different internal coupling mechanisms are then proposed and designed. The two design examples having the same centre frequency of 10 Hz and respective passband width of 300 and 270 Hz are fabricated for demonstration. High selectivity is observed for both filters. Meanwhile, c is ∼37 dB for the first design example, whereas it is improved to 48.5 dB for the second one with multi‐layered structure. Good agreement can be observed between simulated and measured performances in the authors’ study.