Abstract:A novel criterion for thinning array optimization based on optimal polarization (minimization of the cross-polarization level) is proposed to suppress the cross-polarization level and solve the problem of grating lobes arisen from thinning array in millimeter wave conical phased array. The mathematical model based on the radiation pattern of the radar seeker polarization is developed firstly. Then the optimal polarization mode is chosen by comparing the cross-polarization level of circular polarization with that of linear polarization, and two groups basic parameters are determined sequentially. Finally the Modified Particle Swarm Optimization(MPSO) algorithm is applied to optimize the configurations of the elements under two groups of parameters, and then the criterion for thinned array optimization is obtained by compare the array patterns of the two configurations, thus the grating lobes are effectively suppressed. Simulation results verify the rationality of the proposed principle.