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Group delay flatness and bandwidth enhancement of wideband negative group delay microwave circuit
Author(s) -
Meng Yuwei,
Wang Zhongbao,
Fang Shaojun,
Shao Te,
Liu Hongmei,
Chen Zhi Ning
Publication year - 2020
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.22443
Subject(s) - group delay and phase delay , resistor , wideband , bandwidth (computing) , return loss , center frequency , transmission line , microwave , electrical impedance , electric power transmission , insertion loss , physics , electrical engineering , electronic engineering , optoelectronics , telecommunications , optics , engineering , voltage , band pass filter , antenna (radio) , quantum mechanics
Abstract A wideband negative group delay (NGD) microwave circuit with group delay flatness and bandwidth enhancement is proposed. The proposed negative group delay circuit (NGDC) is composed of a resistor connected by two transmission lines and a parallel branch consisted of a resistor linking with a stepped‐impedance transmission line and two open stubs. By tuning the characteristic impedance of the transmission lines, the flat‐NGD bandwidth is enhanced. For verification, an NGDC with a size of 0.24 λ g × 0.34 λ g is designed, fabricated, and measured. The measurement shows that an NGD time of −0.5 ns at the center frequency of 1.0 GHz is obtained with the NGD bandwidth of 68.6% over 0.668 to 1.365 GHz. Also, the flat‐NGD bandwidth reaches 46.3% or 0.776 to 1.243 GHz with ±8% group‐delay fluctuation while the insertion loss is less than 18.8 dB and return loss is greater than 21 dB.