A waveguide orthomode transducer for 385-500 GHz

Christopher Groppi, Alessandro Navarrini, Goutam Chattopadhyay

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations


We describe the design, construction, and performance of a waveguide Orthomode Transducer (OMT) for the 385-500 GHz band. The OMT is based on a symmetric backward coupling structure with a square waveguide input (0.56x0.56 mm2) and two single-mode waveguide outputs: a standard WR2.2 waveguide (0.56x0.28 mm2) and an oval waveguide with full-radius corners. The OMT is rescaled from a lower frequency design that was developed for the 3 mm band; it was optimized using a commercial 3D electromagnetic simulator. The OMT consists of two mechanical blocks in split-block configuration, fabricated using a CNC micromilling machine. A first prototype copper alloy OMT employing standard UG387 flanges at all ports was fabricated and tested. From 385 to 500 GHz the measured input reflection coefficient was less than -10 dB, the isolation between the outputs was less than -25 dB, the cross polarization was less than -10 dB, and the transmission was ≈-2 dB at room temperature for both polarization channels. The effects of misalignment errors in the OMT performance were studied using electromagnetic simulation. A second OMT version utilizing custom made mini-flanges and much shorter waveguides was designed and will be tested soon. This novel OMT is more tolerant to misalignment errors of the block halves and is expected to have much improved performance over the first prototype.

Original languageEnglish (US)
Title of host publicationMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
StatePublished - 2010
EventMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V - San Diego, CA, United States
Duration: Jun 29 2010Jul 2 2010

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherMillimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V
Country/TerritoryUnited States
CitySan Diego, CA


  • Ortho-mode transducer
  • terahertz waveguide

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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