Wideband branch-line couplers with single-section quarter-wave transformers for arbitrary coupling levels

Seungku Lee, Yongshik Lee

Research output: Contribution to journalArticle

46 Citations (Scopus)


Wideband branch-line couplers with arbitrary coupling levels are demonstrated. By integrating single-section quarter-wave transformers at each port, wideband characteristic with excellent coupling flatness is achieved. Also, a method is demonstrated that introduces intentional mismatch for a further enhancement in bandwidth. Superior structural and design simplicity outperform previous wideband couplers. Branch-line couplers at 3 GHz are demonstrated experimentally that maintain the coupling level within 0.5 dB from the specified 10 dB in as much as a 50.9% bandwidth, with minimum return loss and isolation of 16.3 and 18.7 dB, respectively.

Original languageEnglish
Article number6107591
Pages (from-to)19-21
Number of pages3
JournalIEEE Microwave and Wireless Components Letters
Issue number1
Publication statusPublished - 2012 Jan 1


All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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