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Compact wideband bandpass filter with equiripple response in both magnitude and delay
Author(s) -
Jin Xiuhua,
Huang Xiaodong,
Chen Dong,
Cheng Chonghu
Publication year - 2018
Publication title -
international journal of rf and microwave computer‐aided engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 39
eISSN - 1099-047X
pISSN - 1096-4290
DOI - 10.1002/mmce.21293
Subject(s) - passband , group delay and phase delay , band pass filter , wideband , insertion loss , physics , control theory (sociology) , transmission line , filter (signal processing) , stopband , bandwidth (computing) , mathematics , acoustics , computer science , optics , telecommunications , engineering , electrical engineering , control (management) , artificial intelligence
Aiming at the reduction of the in‐band delay variation, a wideband bandpass filter with equiripple response in both magnitude and group delay is presented and studied. The filter is composed of one section of end‐connected coupled line and two short‐circuited shunt transmission line stubs, all of them are uniform and equal in electrical length. Design formulas are given to calculate the characteristic impedances of the lines to meet the filtering specifications. By changing the coupling strength of the coupled line section, the group delay can be controlled to be equiripple in band, while the remaining equiripple response in magnitude unchanged. For verification, a filter sample is fabricated and measured. In experiment, it exhibits a delay variation of 0.11 ns and minimal insertion loss of 0.2 dB within its passband (| S 11 | < −14 dB) from 0.48 to 1.46 GHz, which validates the theoretical predictions.