Sidelobe reduction of the low profile multi-subarray antenna by genetic algorithm

In this paper, the sidelobe of the low profile multi-subarray antenna for satcom on-the-move (SOTM) is reduced by genetic algorithm (GA). The characteristics of the antenna are analyzed theoretically. It is indicated that the sidelobe level of the antenna is difficult to be reduced by amplitude tapering for its dispersed framework. In order to suppress the sidelobe level of the antenna in the whole elevation scan range, the subarray distances are optimized by GA. Two types of the antennas, the fixed-space and the active-space multi-subarray antennas, are analyzed respectively. Then the effects of amplitude perturbation on sidelobe cancellation are discussed under two conditions, i.e., the initial subarray distances and the optimal subarray distances. Simulation results prove the validity of the theoretical analysis, show that the perturbation of subarray distances can suppress the sidelobe level effectively, and the perturbation of amplitude is almost ineffective in sidelobe reduction. The conclusions can be used as the reference to the design of the multi-subarray antenna and other antennas whose array calibrations are discontinuous.