Use of subarrays in linear array for improving wide angular scanning performance

The scanning performance of wide-angular scanning linear arrays is primarily degraded by the limited angular profile of the employed elements' patterns. This paper introduces an innovative strategy for compensating this degradation by using subarrays. Our design uses a uniform linear array with half-wavelength spaced elements, supplemented by subarrays that are symmetrically placed at its edges. The employed subarrays have controlled patterns, favoring some directions for effective scan-loss compensation (SLC) and suppressing other directions for lowering the sidelobes level (SLL). Two types of feeding configurations, making use of fixed power dividers in combination with 1-bit phase switch, are used for producing the desired patterns. The complete array design and physical validation, starting from the elements, continuing with the subarrays and ending with the system integration are also discussed in detail. The integration of the subarrays yields notable performance improvements at large scanning angles when compared with uniform linear arrays. The peak and first SLL of -14.1 dB, and the SLC of 2 dB are obtained when the array with CUP antennas as elements is scanned to the maximum scan angle direction.