Abstract:Widely sparse radar has merits such as anti-interference and anti-destruction capability. However, its radiation pattern will contain a large number of high side-lobe due to the sparse array elements. This paper proposes a beam- forming method by combining intra-pulse frequency agility signals, which can form lower side-lobe level while maintaining the main-lobe level by emitting signals of different frequencies in pulses group of the radar and coherently synthesizing the signals of different frequencies in the airspace. By combining with the genetic algorithm and then setting appropriate constraints and fitness functions, the radiation pattern with lower side-lobe flap can be formed after iterative optimization. The simulation results show that after optimization by this method, the sidelobe level of widely sparse linear array is reduced to -11.85dB, and the azimuthal and pitch sidelobe levels of widely sparse planar array are reduced to -14.18dB and -14.73dB respectively. The method can effectively reduce the side-lobe level of the widely sparse array.