Symmetric/asymmetric H-plane horn fed offset parabolic reflector antenna with switchable pencil/fan-beam radiation characteristics

This paper presents a modified offset parabolic reflector antenna design with easily switchable pencil/fan-beam radiation patterns for X-band tracking, scanning and surveillance microwave radar systems. The modified offset parabolic reflector antenna, combined with an array of flat aluminum plates at the bottom, is fed through symmetric/asymmetric H-plane feed horn antennas. An effective measured pencil-beam/fan-beam switching performance has been achieved as a result of setting the flares of the H-plane feed horn antenna symmetrically and asymmetrically, without making any changes in the geometry of the offset parabolic reflector antenna.