Limited Scan-Angle Phased Arrays Using Randomly Grouped Subarrays and Reduced Number of Phase Shifters

This article presents randomly grouped subarray techniques to reduce the number of phase shifters in a 2-D phased array while maintaining a certain scan range in the azimuth and elevation planes and keeping sidelobes below a specified level. It is shown that controlling random groups of elements in such a manner suppresses these grating lobes and allows the use of fewer phase shifters. Guidelines for finding the best partition of a phased array into random subgroups are presented. It is shown that 75% reduction in phase shifters can be achieved while maintaining a 40° scan range in the azimuth plane, 15° scan range in the elevation plane, and keeping -10 to -12 dB sidelobes without tapering and with 6 dB taper. Other partitions are also presented with up to 88% reduction in phase shifters while maintaining a 5° scan range in elevation. Measurements on a 16×16 2-D phased array at 14 GHz are used to confirm the performance of randomly partitioned phased arrays. Application areas are in arrays with limited scan angle in the elevation plane, such as automotive radars, aircraft landing systems, and point-to-point communication systems.