Evolutionary optimization for pattern synthesis and reduction of mutual coupling of linear antenna arrays

Optimal design of antenna arrays to minimize the mutual coupling effects in the geometrical arrangements of the linear antenna array (LAA) and circular antenna array (CAA) is dealt with in this work. Two different cases are considered to reduce the effect of LAA and CAA: Case-1 in which the current excitations of the antenna array are considered to get the optimal radiation pattern of two geometry called LAA and CAA and Case-2 in which inter-element spacing and current excitations are both optimized for LAA geometry. A cost function that involves the mutual coupling factor as an optimization factor is developed to reduce the side lobe level (SLL), which takes mutual coupling effects into consideration. Excitation values and inter-elemental spacing are optimized using particle swarm optimization (PSO). In LAA, for 8-, 12-, 16-element arrays, SLLs are reduced by -15.52, -16.71, and -17.78 dB in Case-1. For the same sets of element arrays, SLLs were reduced by -17.35, -19.71, and -20.26 dB in Case-2. In CAA, the current excitations of the antenna array are optimized. For 8-, 12-, and 16- element arrays, SLLs are reduced to -7.405, -10.52, and -9.43 dB, respectively. The arrays coded with the help of MATLAB based computation and the results obtained by MATLAB are validated by using CST.