Multi-Beam Forming and Optimization for Active Phased Array Antenna Using Genetic Algorithm

In this paper, the optimized results of multi-beam forming for an active phased array antenna are presented. In the case of a horn radiator, to implement equal main beamwidths and a low side-lobe level in the principal planes, a circularly polarized dual-mode horn antenna with the gain over 14.5 dBi is designed and fabricated at the Ka-band, which is composed of a conical horn, polarizer, and transducer. In the case of multi-beam forming, when several main beams are simultaneously generated within a limited scanning range, large side-lobes can be observed among the main beams. To overcome this phenomenon, an evolutionary technique, such as a genetic algorithm, is applied to the optimization of a multi-beam pattern. It is shown that the proposed method can significantly reduce the outer side-lobe level as well as the inner side-lobe level of the simultaneous multi-beam pattern.