Design and analysis of swapped port coupler and its application in a miniaturized butler matrix

Yae Suk Jeong, Tae Wook Kim

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


This paper presents a novel size reduction technique for designing a Butler matrix using a new type of coupler. This coupler is half the length of a conventional coupler and has a swapped port characteristic wherein the locations of the isolation and coupled ports are switched. These features make the new coupler, called the swapped port coupler, effective for reducing the size of the Butler matrix. The behavior of the swapped port coupler was mathematically analyzed, and its design equation was derived. Furthermore, the proposed coupler was employed to design a miniaturized Butler matrix. The area of this Butler matrix was 70×70 mm2, and its operating frequency was 1 GHz. When the area was normalized to the frequency, the area of the proposed Butler matrix was 10% of a conventional Butler matrix.

Original languageEnglish
Article number5427146
Pages (from-to)764-770
Number of pages7
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number4
Publication statusPublished - 2010 Apr

Bibliographical note

Funding Information:
Manuscript received June 11, 2009; revised October 11, 2009. First published March 08, 2010; current version published April 14, 2010. This work was supported by the National Research Foundation of Korea (NRF) under Grant 2009-8-1535 funded by the Korea Government.

All Science Journal Classification (ASJC) codes

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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