Compact wideband bowtie dipole orthomode transducer
Journal article, 2019

A compact wideband orthomode transducer (OMT) with an octave bandwidth is proposed for a 0.56-1.12 GHz receiver system in the five hundred meter aperture spherical radio telescope. The OMT operates in a cryostat at a temperature of 70 K and therefore it is critical to minimize its dimension while insuring good electrical properties. The complete OMT comprises 2 bowtie dipoles orthogonally arranged in a circular waveguide. Because of the innovative structure, competing modes, TM01 TE21, and TE01, have been effectively suppressed, and the bandwidth of the dominate mode TE11 has achieved to 2.08:1. The final optimized OMT has a length of 300 mm, shorter than a half of the popular quardruple-ridged waveguide OMT. Measurements at room temperature agree well with simulation results, with a reflection coefficient below -10 dB for both polarizations and cross-coupling levels of -30.5 dB over the whole required frequency range.

FAST telescope

radio astronomy


orthomode transducers


Jin Fan

National Astronomical Observatory China

Kai Zhu

National Astronomical Observatory China

Jian Yang

Chalmers, Space, Earth and Environment, Onsala Space Observatory

Chalmers, Electrical Engineering, Communication and Antenna Systems, Antennas

Yihua Yan

National Astronomical Observatory China

Microwave and Optical Technology Letters

0895-2477 (ISSN) 1098-2760 (eISSN)

Vol. 61 4 883-885

Key Technology Developments for Ultra-Wideband Array Radio Astronomy Systems and Investigation of New Concepts for Future Millimeter and Terahertz Radio Telescopes

The Swedish Foundation for International Cooperation in Research and Higher Education (STINT), 2016-06-15 -- 2019-06-30.

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