Double-Ridged Waveguide Orthomode Transducer (OMT) for the 67–116-GHz Band
- 169 Downloads
A high-performance low-loss high-reflection-loss compact double-ridged waveguide orthomode transducer (OMT) for the 67–116 GHz band has been designed, fabricated, and tested. The focus in the design has been to achieve the best possible performance while keeping the design compact and fabrication as simple as possible. The designed OMT is based on a double-ridged waveguide Boifot junction followed by a main arm with an E-plane bend, and two side arms which are combined into a Y-junction. Wideband performance has been achieved by careful control of the waveguide width at the waveguide junction, and by the use of a variable width septum. The design is very compact and can be fabricated by conventional computer numerical control (CNC) milling techniques in two split blocks. The output waveguides are standard WR-10 rectangular waveguides. Prototype OMTs have been fabricated and tested with good agreement with simulations. The measured insertion loss is around 0.15 dB, the reflection loss is better than 23 dB, and isolation and cross-polarization are lower than – 45 dB at all frequencies. This OMT is intended to be used in cryogenic low-noise receivers for radio astronomy. To the extent of our knowledge, this is the best reported performance for an OMT over a 55% fractional bandwidth at W-band frequencies.
KeywordsOrthomode transducers Waveguide junctions Millimeter-wave circuits Polarization splitter Radio astronomy
The authors would like to thank the rest of the team members of the Receiver Development team at NAOJ/Advanced Technology Center and Chile Observatory, especially to K. Kaneko for preparing the fabrication drawings of the prototype components. We are also grateful to the rest of the members of the ALMA band 2+3 consortium, led by Dr. P. Yagoubov at ESO for fruitful discussion and collaboration. Finally, we would like to thank Dr. Y. Hasegawa and Prof. H. Ogawa at Osaka Prefecture University for useful discussion and collaboration in OMT designs.
This work was supported by JSPS KAKENHI Grant Number 15H02074.
- 1.J. Uher, J. Bornemann, and U. Rosenberg, Waveguide Components for Antenna Feed Systems: Theory and CAD, section 3.8, Artech House, Norwood, 1993, pp. 371–445Google Scholar
- 4.D. Henke and S. Claude, Design of a 70-116 GHz W-band Turnstile OMT, 2014 44th European Microwave Conference, pp. 456–459, Rome (Italy), 6–9 Oct. 2014Google Scholar
- 5.A.M. Boifot, E. Lier, T. Schaug-Pettersen, Simple and broadband orthomode transducer, IEEE Proceedings, Vol. 137, Pt. H, No. 6, pp. 396–400, Dec. 1990Google Scholar
- 6.E.J. Wollack, W. Grammer, J. Kingsley, The Boifot Orthomode Junction, ALMA memo 425, May 2002. Available: http://library.nrao.edu/public/memos/alma/main/memo425.pdf. Accessed 8 June 2018
- 7.E.J. Wollack, W. Grammer, Symmetric Waveguide Orthomode Junctions, in Proc. 14th Int. Symposium on Space Terahertz Technology, Tucson, AZ, April 22–24, 2003, pp. 169–176Google Scholar
- 8.G. Narayanan, N.R. Erickson, Full-waveguide band orthomode transducer for the 3 mm and 1 mm bands, in Proc. 14th Int. Symposium on Space Terahertz Technology, Tucson, AZ, April 22–24, 2003, pp. 508–512Google Scholar
- 9.A. Dunning, Double ridged orthogonal mode transducer for the 16-26 GHz microwave band, in 4th Workshop on the Applications of Radio Science (WARS02), Leura (Australia), February 20–22, 2002, pp. 1–3Google Scholar
- 10.G. Moorey, R. Bolton, A. Dunning, R. Gough, H. Kanoniuk, L. Reilly, A 77-117 GHz cryogenically cooled receiver for radio astronomy, in 6th Workshop on Applications of Radio Science (WARS06), Leura (Australia), February 15–17, 2006, pp. 1–7Google Scholar
- 11.S. Asayama, and M. Kamikura, Development of Doubled-Ridged Waveguide Orthomode Transducer for the 2mm Band, J Infrared Millimeter and Terahertz Waves, Vol. 30, pp. 573–579, June 2009Google Scholar
- 12.G. Chattopadhyay, and J.E. Carlstrom, Finline Ortho-Mode Transducer for Millimeter Waves, IEEE Microwave and Guided Wave Letters, Vol. 9, No. 9, pp. 339–341, Sept. 1999Google Scholar
- 13.A. Navarrini, and R. Nesti, Symmetric Reverse-Coupling Waveguide Orthomodo Transducer for the 3-mm Band, IEEE Trans. Microwave Theory and Techniques, Vol. 57, No. 1, pp. 80–88, Jan. 2009Google Scholar
- 14.G. Chattopadhyay, et al., A 96-GHz Ortho-Mode Transducer for the Polatron, IEEE Microwave and Guided Wave Letters, Vol. 8, No. 12, pp. 421–423, Dec. 1998Google Scholar
- 15.A. Dunning, S. Srikanth, and A.R. Kerr, A Simple Orthomode Transducer for Centimeter to Submillimeter Wavelengths, in Proc. 20th Int. Symposium on Space Terahertz Technology, Charlottesville, VA, 20–22 April 2009Google Scholar
- 16.M. Kamikura, et al., Development of a Submillimeter Double-Ridged Waveguide Ortho-Mode Transducer (OMT) for the 385–500 GHz Band, J Infrared Millimeter and Terahertz Waves, Vol. 31, pp. 697–707, June 2010Google Scholar
- 17.Y. Sekimoto, et al., Development of ALMA Band 8 (385-500 GHz) Cartridge, in Proc. 19th Int. Symposium on Space Terahertz Technology, Groningen, the Netherlands, 28–30 April 2008Google Scholar
- 18.S. Asayama, and T. Nakajima, Development of a Smooth Taper Double-Ridge Waveguide Orthomode Transducer for a New 100 GHz Band Z-machine Receiver for the NRO 45-m Radio Telescope, Pub. Astronomical Society of the Pacific, Vol. 125, Number 924, pp. 213–217, Feb. 2013Google Scholar
- 19.I. Barrueto, N. Reyes, P. Mena, and L. Bronfman, A Broadband Orthomode Transducer for the new ALMA Band 2+3 (67-116 GHz), 2016 Global Symposium on Millimeter Waves (GSMM) & ESA Workshop on Millimeter-Wave Technology and Applications, Espoo (Finland), June 2016, pp. 1–4Google Scholar
- 20.G.A. Fuller, et al., The Science Case for ALMA Band 2 and Band 2+3, arXiv:1602.02414. Available: https://arxiv.org/abs/1602.02414
- 21.T. Minamidani, et al., Development of the new multibeam 100 GHz band SIS receiver FOREST for the Nobeyama 45-m telescope, Millimeter, Submillimeter, and Far-Infrared Dectectors and Instrumentation for Astronomy VIII, Proc. SPIE Vol. 9914, 99141Z, pp. 1–10Google Scholar
- 22.A. Wootten and A. R. Thompson, The atacama large millimeter/submillimeter array, Proc. IEEE, vol. 97, no. 8, pp. 1463–1471, Aug. 2009Google Scholar
- 23.D. Dousset, S. Claude, and K. Wu, A Compact High-Performance Orthomode Transducer for the Atacama Large Millimeter Array (ALMA) Band 1 (31-45 GHz), IEEE Access, Vol. 1, pp. 480–487, July 2013Google Scholar
- 24.A. Gonzalez, et al., ALMA band 2+3 (67-116 GHz) optics: Design and first measurements, 2016 IEEE Int Symposium on Antennas and Propagation (APS-URSI), pp. 1195–1196, June 2016, Fajardo (Puerto Rico)Google Scholar
- 25.V. Tapia, R. Nesti, A. Gonzalez, et al., An ultra-broadband optical system for ALMA band 2+3, Millimeter, Submillimeter, and Far-Infrared Dectectors and Instrumentation for Astronomy VIII, Proc. SPIE Vol. 9914, 99142X, pp. 1–7, June 2016Google Scholar
- 26.D. Cuadrado-Calle, et al., Broadband MMIC LNAs for ALMA Band 2+3 With Noise Temperature Below 28K, IEEE Trans. on Microwave Theory and Techniques, Vol. 65, No. 5, pp. 1589–1597, May 2017Google Scholar
- 27.Y. Tang, et al., Cryogenic W-band LNA for ALMA band 2+3 with average noise temperature of 24 K, Microwave Symposium (IMS) 2017 IEEE MTT-S International, pp. 176–179, June 2017.Google Scholar
- 28.MIG WaspNET, Software description. Available: http://www.mig-germany.com/.
- 29.High Frequency Structure Simulator (HFSS). Sofware Description. Available: http://www.ansys.com/.
- 30.A. R. Kerr, Effects of misalignment of square waveguide joints, National Radio Astronomy Observatory, EDTN 211, 12 March 2009. Available at: http://www.gb.nrao.edu/electronics/edtn/edtn211.pdf