Hybrid Parasitic Linear Array Antenna for Fine Beamsteering Applications

This paper presents an antenna that utilizes two beam steering techniques in concert in order to improve the antenna gain and steering resolution. Phased array steering is employed to achieve coarse resolution beam steering while parasitic steering is employed to achieve fine resolution beam steering within each coarse angle step provided by the phased array. A proof-of-concept antenna operating at 11.5 GHz was designed, fabricated and measured. The antenna incorporated 3-bit phase shifters and achieved a steering resolution of 1° over a steering range of ±40°. In order to achieve the same steering resolution, using a conventional array, it would be necessary to use 6-bit phase shifters. When compared to a conventional array the realised gain of the novel antenna was 4 dB higher. The antenna shows an improvement in scan loss when steering off boresight. The key advantage of the proposed Hybrid Parasitic Array Antenna is its low profile and high steering speed when compared with the alternative steering techniques.