Broadband cylindrical‐cavity directional filter

Yoji Isota*, Moriyasu Miyazaki, Osami Ishida

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


The diplexing bandwidth of a cylindrical‐cavity directional filter is restricted of coupling of the coupling hole, which is installed in order to excite a circular polarization on the common walls of the input and output rectangular waveguides and in the adjacent cylindrical cavity. This paper proposes a method of increasing the coupling of circular polarization by means of an iris‐loaded cross‐coupling hole (consisting of an iris mounted on the crossed‐coupling hole of a rectangular waveguide). The results of analysis of the magnetic field distribution and the magnetic field intensity in a rectangular waveguide loaded with an iris are described. It shown that the iris‐loaded cross‐coupling hole is effective in exciting a circular polarization and increasing coupling. The results of a trial fabrication of a directional filter using this type of coupling hole are presented. In the case of a three‐stage maximally flat K band filter, a passband relative bandwidth of 2.7 percent was obtained. This bandwidth is three times as great as in conventional filters. Hence, the range of application of the cylindrical cavity directional filter has been extended.

Original languageEnglish
Pages (from-to)85-91
Number of pages7
JournalElectronics and Communications in Japan (Part I: Communications)
Issue number6
Publication statusPublished - 1993
Externally publishedYes


  • Waveguide filter
  • cylindrical cavity resonator, iris‐loaded cross‐coupler
  • directional filter
  • multibeam antenna

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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