Additive Manufacturing of Interdigital Filters with Arbitrary Line Cross Section

Johannes J.P. Venter, Riddhi Maharaj, Tinus Stander

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


This article investigates the novel use of additive manufacturing (AM) in the production of interdigital cavity filters. It is found that AM enables the production of interdigitated pins of complex cross-sectional geometry, leading to the development of a suitable synthesis method using a commonly available 2-D eigenmode port impedance solver. The method is validated by manufacturing an L-band interdigital filter of 70% fractional bandwidth with triangular bars through selective laser melting, as well as a classical design using rectangular bars. It is found that triangular bars obtain similar coupling to rectangular bars over the average of 35% wider spacing gaps, reducing its sensitivity to manufacturing error. In addition, neither filter requires postproduction tuning, although the bars do warp slightly during printing. These results illustrate the advantages of using AM for the synthesis of wideband interdigital filters.

Original languageEnglish
Article number8963748
Pages (from-to)686-693
Number of pages8
JournalIEEE Transactions on Components, Packaging and Manufacturing Technology
Issue number4
Publication statusPublished - Apr 2020
Externally publishedYes


  • Additive manufacturing (AM)
  • bandpass filters
  • interdigital filters
  • microwave filters
  • selective laser melting (SLM)
  • TEM-line filters
  • wideband filters

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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