X-band feed for 4.6m axially displaced ellipsoid reflector antenna capable of tracking using monopulse comparator

In this paper, the design of a X-Band feed for a 4.6m Ship-borne Transportable Terminal (SBT) is presented. The SBT is known for its application of providing extended support for Telemetry, Tracking and Command (TT&C) in the sea. The configuration of SBT comprises of a five antenna feed system where the central element provides the sum pattern and the four adjacent elements, as a 2×2 array, are used for generating the difference patterns. The complete feed system is installed at the focii of the reflector antenna in Axially Displaced Ellipsoid (ADE) configuration. The designed central X-Band feed has a good circularly symmetric co-pole patterns and an isolation better than 15 dB over 19% bandwidth. This element provides cross-pol isolation better than 25db at the required uplink (7.2 GHz ) and the downlink (8.5 GHz) frequency.