Design Methodology of Transmission-Line Quadruplet Filters Supported by Rigorous Circuit Transformations

Jongheun Lee, Juseop Lee

Research output: Contribution to journalArticlepeer-review


This article presents a novel and rigorous technique to design transmission-line quadruplet filters. Unlike the prevailing approaches relying on electromagnetic (EM) simulations for coupling tests, the proposed design technique completely counts on rigorous circuit transformations. As all design parameters (lengths and line impedances) can be rigorously calculated from the design equations provided in this work, a quadruplet filter can be designed without conducting EM simulations to find the dimensions delivering the desired coupling coefficients. Our design approach will be demonstrated with the fourth-and fifth-order filter examples, both of which were fabricated and measured for validation.

Original languageEnglish
Pages (from-to)2639-2651
Number of pages13
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number6
Publication statusPublished - 2023 Jun 1

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) under Grant NRF-2022R1A2B5B01001340.

Publisher Copyright:
© 1963-2012 IEEE.


  • Resonator filter design

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Radiation
  • Electrical and Electronic Engineering


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