Array Pattern Synthesis Using Digital Phase Control by Quantized Particle Swarm Optimization

A modified PSO algorithm called quantized PSO (QPSO) is described for the synthesis of antenna array patterns by digital phase shifters. The solution space of the QPSO algorithm is restricted to finite quantized integer values of the array phase coefficients. The QPSO search for an optimal solution within the available quantized values of the digital phase shifters to minimize the fitness function that includes the SLL value and interference suppression while maintains the main beam unchanged. The array factor is expressed using a linear transform based on discrete cosine transform (DCT) with pre-computed DCT matrix which allows a high speed computation of the fitness function. The results show better synthesis performance using QPSO, as compared to BPSO and efficient computation time for large arrays.