Planar arrays with unequally spaced elements

The application of the optimization technique known as dynamic programming to the design of thinned planar arrays with unequally spaced elements is described. Two different approaches were investigated. In one method the planar aperture was considered to consist of a number of concentric ring arrays and dynamic programming was applied to determining the radii of the rings which yielded radiation patterns with the minimum peak side-lobe. In the other method the planar array was divided into an even number of equal sectors with elements identically located in each sector. Both methods were selected to avoid excessive calculation times. With the aid of large digital computers designs were obtained and radiation patterns computed for 40¿ diameter circular planar arrays and for various degrees of thinning. The results differed from those obtained by other unequally spaced array design methods in that the side-lobes of the radiation pattern tended to decrease with increasing distance from the main beam.