Generalized miniaturization method for coupled-line bandpass filters by reactive loading

Seungku Lee, Yongshik Lee

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


This paper presents a generalized miniaturization method for coupled-line bandpass filters by reactive loading, including the series-inductive loading method that is proposed in this work. It is shown that bandwidth reduction seen in the previous miniaturization method of shunt-capacitive loading is a special case. In fact, one can choose a coupled-line filter to be miniaturized with its bandwidth reduced, expanded, or maintained after miniaturization. The ratio of the bandwidths before and after miniaturization plays an important role in determining the even-/odd-mode impedance, as well as the reactance levels after miniaturization. Therefore, the freedom in choosing the bandwidth ratio provides a great flexibility in miniaturizing coupled-line filters since one can choose an appropriate bandwidth ratio to maintain the impedance and reactance at practical levels after miniaturization. The proposed generalized miniaturization method enables filter designs focused on size reduction, improved stopband response, low-cost fabrication, or a combination of these, which are verified by experimental results.

Original languageEnglish
Article number5540255
Pages (from-to)2383-2391
Number of pages9
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number9
Publication statusPublished - 2010 Sept

Bibliographical note

Funding Information:
Manuscript received March 04, 2010; revised May 19, 2010 and May 31, 2010; accepted June 19, 2010. Date of publication August 05, 2010; date of current version September 10, 2010. This work was supported by the Low Observable Technology Research Center, Defense Acquisition Program Administration, by the Agency for Defense Development of Korea, and by the Korea Communications Commission (KCC) under the CPRC Program supervised by the Institute for Information Technology Advancement (IITA) (IITA-2009-C1091-0901-0007).

All Science Journal Classification (ASJC) codes

  • Radiation
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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