A Tri-Ridge Flared Horn Reflector Antenna Feed for Radio Astronomy

Tri-ridge waveguides (TRWs) have been shown to have wider single-mode bandwidth when compared to quad-ridged waveguides (QRWs) [1], which presents an opportunity for the design and optimization of Tri-Ridge Flared Horns (TRFHs) to compete against the widely accepted Quad-Ridge Flared Horns (QRFHs) as reflector feeds in radio astronomy. Fig. 1 shows an example of a TRFH design, showing the 120° separation of the ridges. This talk will present design methods and initial results for the performance of a TRFH as a wideband reflector feed. Specific attention will be given to the design of the horn and ridge tapers to guarantee trapped-mode free operation, as well as provide controlled wideband radiation and impedance performance. Discussion of the three-way digital orthogonal-mode transducer as well as the details of the optimization method (with a goal of maximum receiving sensitivity over a nominally 3.5:1 bandwidth) will be provided.