Wide bandwidth arbitrary phase difference branch line coupler

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Pages (from-to)2241-2245
Journal / PublicationMicrowave and Optical Technology Letters
Issue number9
Online published27 Jun 2017
Publication statusPublished - Sep 2017


As a conventional branch line coupler (BLC) is limited toa phase difference of 90°, different phases have typically been realized by cascading additional phase-shifters,which inevitably increase the circuit size. This articlepresents a BLC capable of achieving a combined widebandwidth and arbitrary phase difference. This is achievedby inserting a phase compensation network directly ineach of the series branch lines, which effectively modifiesthe electrical lengths. A prototype 60°/–120° coupler hasbeen fabricated and experimentally characterized toachieve a 0.5-dB magnitude imbalance, 5° phase stability,return loss better than 215 dB, and isolation better than214 dB from 2.3 to 3.5 GHz.

Research Area(s)

  • 3-dB branch line coupler, arbitrary phase difference, phase compensation network