Inline interdigital pseudo-elliptic helical resonator filters

E. Doumanis*, G. Goussetis, S. A. Kosmopoulos

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


A new inline coupling topology for narrowband helical resonator filters is proposed that allows to introduce selectively located transmission zeros (TZs) in the stopband. We show that a pair of helical resonators arranged in an interdigital configuration can realize a large range of in-band coupling coefficient values and also selectively position a TZ in the stopband. The proposed technique dispenses the need for auxiliary elements, so that the size, complexity, power handling and insertion loss of the filter are not compromised. A second order prototype filter with dimensions of the order of 0.05 lambda, power handling capability up to 90 W, measured insertion loss of 0.18 dB and improved selectivity is presented.

Original languageEnglish
Pages (from-to)400-402
Number of pages3
JournalIEEE Microwave and Wireless Components Letters
Issue number8
Publication statusPublished - Aug 2011


  • quasi-elliptic
  • dispersive-coupling
  • interdigital filters
  • helical resonator
  • UHF
  • filters


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