Investigation of a wideband 90° hybrid coupler with an arbitrary coupling level

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

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  • Leung Chiu
  • Quan Xue


Original languageEnglish
Article number5430901
Pages (from-to)1022-1029
Journal / PublicationIEEE Transactions on Microwave Theory and Techniques
Issue number4
Publication statusPublished - Apr 2010


This paper presents a new class of wideband 90 ° hybrid coupler with an arbitrary coupling level. The physical size of the proposed coupler is close to that of a conventional two-section branch-line coupler, but it has an additional phase inverter. The impedance bandwidth of the proposed coupler is close to that of a four-section branch-line coupler. The proposed coupler is a backward-wave coupler with a port assignment different from that of a conventional branch-line coupler. The design formulas of the proposed coupler are proved based on its even- and odd-mode half structures. We demonstrated three couplers at the center frequency of 2 GHz with different design parameters. © 2006 IEEE.

Research Area(s)

  • 90° hybrid coupler, Bandwidth enhancement, Parallel-strip phase inverter