A compact tri-band microstrip filter with independently tunable passbands and high selectivity

Research output: Contribution to journalArticlepeer-review


  • Fan Zhang
  • Yang Gao
  • Yi Wang
  • Yi Zhang
  • Jun Xu

Colleges, School and Institutes

External organisations

  • University of Electronic Science and Technology of China
  • Zhengzhou University


This paper presents a compact tunable tri-band filter with independently controlled passbands and high selectivity. The filter is comprised of three pairs of varactor-loaded λ/4 short-circuited resonators. Each passband of the filter can be independently tuned by varying the voltage applied to the corresponding resonators. In addition, a source-load coupling structure is employed to produce transmission zeros (TZs) achieving high selectivity. A prototype tunable tri-band microstrip filter is implemented. The experiment results show that the three passbands have tuning ranges of 0.81-0.99 GHz, 1.34-1.54 GHz, and 1.8-2.03 GHz, respectively.

Bibliographic note

Publisher Copyright: Copyright © 2019 The Institute of Electronics, Information and Communication Engineers Copyright: Copyright 2020 Elsevier B.V., All rights reserved.


Original languageEnglish
Article number20190589
Pages (from-to)1-3
Number of pages3
JournalIEICE Electronics Express
Issue number22
Publication statusAccepted/In press - 17 Oct 2019


  • Microstrip filter, Tri-band filter, Tunable filter