A Tri-Ridged Flared Horn for Radio Astronomy Applications

The research in this dissertation covers the modal analysis of three-fold symmetric structures, specifically the Tri-Ridged Wavguide (TRWG). The modal properties of these structures show high single-mode bandwidth, which presents an opportunity to check for viability in radio astronomy applications. To en-able such a study, an algorithm was developed to track and identify the modes in TRWG by using CST - a commercial three-dimensional electromagnetic analysis package. With the results of this algorithm, a modal analysis is presented for TRWGs. On this basis, a TRWG Orthomode Transducer (OMT) is designed to be cascaded with a Tri-Ridged Flared Horn (TRFH) to show that the fundamental mode will propagate with a high single-mode bandwidth. A goal function based on an S-parameter analysis for the reflection coefficient optimisation is also found. The TRWG OMT features a reference port that can be used for gain calibrations. The best result for this TRWG OMT is a maximum of −10 dB reflection coefficient across a 1.2 − 3.5 GHz bandwidth. The mode tracking algorithm is also used for a modal analysis of the TRFH. The TRFH is designed and optimised for maximum receiving sensitivity, by using existing methods and techniques used for other antennas in radio astronomy. The optimised TRFH showed a reflection coefficient of −20 dB when a perfect OMT is used in CST. When including the OMT, the maximum receiving sensitivity of 15 m2/K achieved on the shaped ngVLA reflector remains unchanged.

Grantor dc:publisher

Stellenbosch : Stellenbosch University

Year dc:date.issued

2026

Author dc:creator

• Du Toit, Zainodean

Advisors dc:contributor.advisor

• De Villiers, I. L.
• Lehmensiek, Robert

Language dc:language.iso

en

Repository record dc:identifier.uri

https://scholar.sun.ac.za/handle/10019.1/135783

OAI identifier oai:identifier

oai:scholar.sun.ac.za:10019.1/135783