A novel twin-horn feed for multi-beam remote sensing reflector antenna

Multi-beam reflector antennas attract more interest nowadays with the ever increasing requirements of spaceborne applications. In a recently proposed project for spaceborne remote sensing application, a 3.5-m offset parabolic reflector antenna with a novel feed arrangement is designed which optimally satisfies some specific requirements. It features two sets of feeds located in the focal plane to generate two scanning beams. Since the antenna is required to spin at high speed with an orbit altitude of 800 kilometers, the twin-horn structure is employed to better receive remote sensing signals reflected back from the earth surface. Each twin-horn feed consists of two closely positioned corrugated horns to transmit and receive signals, respectively. To address the demanding requirement on beam separation of the twin-horn feed, the integrated twin-horn structure is utilized, and its parameters are properly adjusted to provide the desired feed taper. The twin-horn feed is simulated, fabricated, and measured, and the simulation and measurement results agree very well. The far-field pattern of the reflector antenna illuminated by the measured twin-horn feed pattern is also obtained, and the simulation results match well with the design goals.