Method and apparatus for four-beam radar

Claim 1

A four-beam radar apparatus comprising: means for generating a driving signal; means connected to said generating means, for splitting said driving signal into 4n 2 driving signals where n is a nonzero positive integer; 4n 2 phase shifters divided in a predetermined fashion into n 2 phasing groups of four phase shifters apiece for generating predetermined phase shifts; 4n 2 array elements arranged in a 2n×2n square matrix divided in a predetermined fashion into n 2 element groups of four array elements apiece; n 2 switching means respectively associated with one of said n 2 phasing groups and one of said n 2 element groups for selectably and alternately interconnecting said four elements in said element group and said four phase shifters in said phasing group in one of four alternate predetermined interconnections; said 4n 2 array elements being arranged at positions (±j, ±k) where j and k are positive integers between one and n inclusively; each ordered coordinate pair j, k determining one of said n 2 element groups; and each ordered pair j, k determining one of said phasing groups, the four phase shifts being created by said group being determined by the product of a unit phase shift times ±x or ±y, where x equals (j+k-1), and where y equals (j-k).