Gain Degradation of KVN 21-m Shaped Cassegrain Antenna due to Misalignment of Antenna Optics

Abstract

In this paper, gain loss of KVN (Korean VLBI Network) 21-m shaped Cassegrain antenna due to misalignment of antenna optics is calculated using ray-tracing method. It enables us to estimate alignment tolerances of feed and sub-reflector positioning. According to numerical results, KVN 21-m shaped Cassegrain antenna's gain loss is more sensitive to positions of feed and sub-reflector than in case of the equivalent classical Cassegrain antenna. The result of calculation is believed to be utilized as a possible guideline when checking the performance of the antenna system.

Keywords

• ray tracing
• antenna optics
• shaped Cassegrain antenna
• alignment tolerance