A Q‐band compact high‐performance double‐ridged orthomode transducer. Issue 12 (8th October 2019)

• Record Type: Journal Article
• Authors: Zhong, Weiye; Yin, Xiaoxing; Shi, Shengcai
• Is Part Of: International journal of RF and microwave computer-aided engineering. Volume 29:Issue 12(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-10-08
• Subjects: double‐ridged -- orthomode transducers (OMTs) -- radio astronomy; Microwave devices -- Computer-aided design -- Periodicals; Computer-aided engineering -- Periodicals; 621.3813
• DOI: 10.1002/mmce.21982
• Languages: English
• ISSNs: 1096-4290

Abstract

Abstract: In this article, a Q‐band compact waveguide orthomode transducer (OMT) based on a stepped double‐ridged waveguide is presented. By using a symmetrical structure, good output return losses of above 20 dB are obtained from 35 to 50 GHz. In particular, the measured insertion losses are as low as 0.15 to 0.4 dB over the entire band for both polarization channels with an improved assembly configuration. The measured cross‐polarization levels are well below −37 dB, while the circular‐polarized output port isolation is less than −20 dB combined with a feed horn and a differential phase shifter. The developed OMTs have been used in a Q‐band two‐beam cryogenic receiver on the Tianma Radio Telescope, contributing only 1 to 2 K noise at an operating temperature around 20 K.