A Compact Axial-Ring Feed Horn and Vacuum Window Model for a Cryogenic Q-band Receiver

A compact front-end design, including an axial-ring corrugated feed horn and a vacuum window, has been designed for a proposed ngVLA Band-5/ Q-band receiver. The electromagnetic performance, optical propagation, and mechanical analysis of the proposed front-end model are presented in this paper. Our design work achieved an optimized compact feed with an aperture efficiency higher than 95%, using shaped optics, and a "top-hat" shaped vacuum window with excellent performance covering the frequency range 30 - 51 GHz for the wide opening-angle ngVLA antenna optics.