Subarrays in linear array configurations, an effective instrument for scan loss compensation

Abstract

A novel approach is proposed for compensating the scan loss in wide-angular scanning array antennas due to the pattern falloff of physical radiators. The method is based on replacing elements in (linear) arrays with sub arrays with enhanced radiation intensity at large angles. This strategy is best applicable in the case of sparse arrays that intrinsically provide the space for accommodating sub arrays. An optimised linear sub array, with 5 dB radiation intensity enhancement at 60° is designed. This sub array is then incorporated in linear array antennas with (approximately) 50% thinning factors. An up to 1.2 dB improvement of the maximum directivity at 60° beam scanning is obtained. The obtained results allow conjecturing that a similar strategy, when applied to planar arrays, will lead to an even more significant scan-loss reduction, this yielding a substantial performance enhancement for wide-angular scanning radar array antennas.