SYNTHESIS OF THINNED PLANAR CONCENTRIC CIRCULAR ANTENNA ARRAYS --- A DIFFERENTIAL EVOLUTIONARY APPROACH

Circular antenna array design is one of the most important electromagnetic optimization problems of current interest. The problem of designing a large multiple concentric planar thinned circular ring arrays of uniformly excited isotropic antennas is considered in this paper. This antenna must generate a pencil beam pattern in the vertical plane along with minimized side lobe level (SLL). In this paper, we present an optimization method based on an improved variant of one of the most powerful real parameter optimizers of current interest, called Difierential Evolution (DE). Two sets of difierent cases have been studied here. First set deals with thinned array design with the goal to achieve number of switched ofi elements equal to 220 or more. The other set contains design of array while maintaining side lobe level (SLL) below a flxed value. Both set contains two types of design, one with uniform inter-element spacing flxed at 0.5‚ and the other with optimum uniform inter-element spacing. The half-power beam width of the synthesized pattern is attempted to maintain flxed at the value equal to that of a fully populated array with uniform spacing of 0.5‚. Simulation results of the designed thinned arrays are compared with a fully populated array for all the cases to illustrate the efiectiveness of our proposed method.