Synthesis of Reactively Controlled Antenna Arrays Using Characteristic Modes and DE Algorithm

A simple yet efficient procedure for the synthesis of reactively controlled 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 the specific requirements on radiation pattern, loading schemes, and/or other 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 finally concluded in terms of the quality of the optimal design, the convergence rate, and the computational complexity.