Reactively loaded antenna array design with characteristic modes and DE algorithm

A simple procedure for the synthesis of reactively loaded antenna arrays is proposed by applying the theory of characteristic modes (CM) to the differential evolution (DE) algorithm. A characteristic mode analysis of an antenna array consisting of N elements is first carried out to identify its different radiating modes. Based on these characteristic modes, the DE algorithm is then employed to seek the optimal mode excitation coefficients according to design specifications. Several circular antenna arrays are successfully synthesized according to main beam direction and maximum sidelobe level. The benefits brought by the theory of CM are illustrated in terms of the quality of the optimal design and the computational complexity.