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Development of Double-Ridged Wavegide Orthomode Transducer for the 2 MM Band

  • Shin’ichiro AsayamaEmail author
  • Mamoru Kamikura
Article

Abstract

This paper describes the design and development of the 2 mm band orthomode transducer (OMT) for the Band 4 cartridge receivers of the Atacama Large Millimeter/Submillimeter Array (ALMA). The OMT consists of a double-ridged waveguide followed by a Bϕifot type junction with a main arm and two side arms. The main arm output is a multi-section step transformer followed by an E-plane bend and an oval waveguide to be realized the OMT with a two-split block using conventional Computer Numerical Control (CNC) milling techniques. The prototype OMT shows return loss of better than 20 dB, cross polarization coupling of better than 30 dB and insertion loss of less than 0.4 dB across 125 – 163 GHz. Furthermore, production feasibility was demonstrated through the evaluation of seven OMTs with a production design. The design of the developed OMT is so simple that it is easily scaled to submillimeter frequencies.

Keywords

Orthomode Transducer (OMT) Double-ridged waveguide Radio Astronomy ALMA 

Notes

Acknowledgment

The author would like to thank T. Wada and M. Inata for testing OMTs. I would also like to thank T. Noguchi and A. Endo for their invaluable comments. I am also grateful to the entire people of the Advanced Technology Center and ALMA-J project office for their useful discussions and support.

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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Advanced Technology Center and ALMA-J project officeNational Astronomical Observatory of JapanTokyoJapan
  2. 2.Department of Astronomy, School of Sciencethe University of TokyoTokyoJapan

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