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Stub‐loaded square loop bandpass filter with equiripple response in both delay and magnitude
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.21297
Subject(s) - stub (electronics) , ripple , passband , band pass filter , control theory (sociology) , group delay and phase delay , bandwidth (computing) , insertion loss , magnitude (astronomy) , chebyshev filter , mathematics , filter (signal processing) , physics , mathematical analysis , optics , computer science , electronic engineering , engineering , telecommunications , quantum mechanics , voltage , computer vision , control (management) , artificial intelligence , astronomy
It is shown that a stub loaded square loop filter, composed of six sections of commensurate transmission line, can achieve equiripple response in both magnitude and group delay simultaneously, when the admittances of the lines are properly chosen. Design formulas are given to calculate the admittances by given specifications such as fractional bandwidth and in‐band magnitude ripple. An interesting property of this filter is that the group delay can be adjusted while the in‐band magnitude response keeps almost unchanged. For verification, a filter sample is designed, fabricated and measured. In experiment, it exhibits a delay variation of 0.22 ns and minimal insertion loss of 0.21 dB within its passband (| S 11 | < −13.8 dB) from 0.48 to 1.52 GHz, which agree well with the theoretical predictions.