A Design and Implementation of Low Cost Wideband Digital Array Antenna Based on Stretch Processing Technique

keywords:stretch processing  digital array antenna  wideband phased array  low cost

Abstract:Wideband phased array radar offers the advantages of high range resolution and the recognition ability for multiple targets, group targets, and high-speed targets. Traditional broadband phased arrays use true time-delay to compensate for aperture fill time, however the cost increases significantly. In this paper, a wideband element-level digital array architecture based on the stretch processing method is proposed. By utilizing the time-domain and frequency-domain translation equivalence of the linear frequency modulation signal waveform, the equivalent aperture fill time is compensated through frequency shift and phase shift after stretch processing. Compared to the design of traditional broadband digital arrays, this method can dramatically reduce the performance requirements of antenna hardware,and greatly reduce the cost of antenna system manufacturing. A comprehensive analysis of the signal processing process and stretch processing method is provided. And an antenna array prototype is developed to verify the T/ R channel compensation and broadband beamforming. Measured results show that the antenna prototype is capable of ±60° scanning in azimuth plane and ±40° scanning in elevation plane, with a bandwidth of 500 MHz in the S-band. The results demonstrate excellent broadband beam performance and accurate lobe scanning, which confirms the validity of the proposed wideband digital architecture for stretch processing. This method can be widely applied to the low-cost design and broadband performance improvement of wideband digital array radar.