Optimization of small reflector antennas for radio astronomy

Abstract

This paper reports simulated and analytical results for 3.8 m symmetric and offset reflector geometries using a wideband feed and concludes that a significant improvement in performance can be obtained using the offset geometry. These performance improvements are a reduction of spillover noise from 28K to 16 K, and an improvement in the sensitivity figure of merit (A_(eff)/T_(sys)) from 0.07 to 0.09 m^2/K. Further performance improvement in offset design were achieved using a ground shield, which reduced the spillover noise to 11 K, and adding a dielectric rod within the wideband feed, which illuminated the antenna to improve sensitivity figure of merit from 0.09 to 0.12m^2/K The use of a mesh material for the offset reflector surface was also investigated. Using these optimizations, arrays of small offset reflectors can be used in future radio astronomy.

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