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
wideband
orthomode transducers
Author
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, Antennas and Optical Networks
Yihua Yan
National Astronomical Observatory China
Microwave and Optical Technology Letters
0895-2477 (ISSN) 1098-2760 (eISSN)
Vol. 61 4 883-885Key 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) (CH2015-6360), 2016-06-15 -- 2019-06-30.
Subject Categories
Other Physics Topics
Other Materials Engineering
Other Electrical Engineering, Electronic Engineering, Information Engineering
DOI
10.1002/mop.31662