Pencil beam pattern synthesis of time-modulated concentric circular antenna array using PSO with Aging Leader and Challenger

Abstract

In this paper, a nine-ring time-modulated concentric circular antenna array (TMCCAA) with isotropic elements has been analyzed based on an evolutionary optimization algorithm called particle swarm optimization (PSO) with Aging Leader and Challenger (ALC-PSO) for the reduction of side lobe level (SLL) and improvement in the directivity. Some other population-based evolutionary algorithms like real-coded genetic algorithm, PSO, and differential evolution (DE) have also been applied for the sake of comparative performance study of the same optimal designs. The comparative case studies as Case-1 and Case-2 are made with three control parameters like inter-element spacing in rings, inter-ring radii, and the switching “ON” times of rings with the help of same algorithms. ALC-PSO performs the dual task of improvement of directivity values as well as minimization of SLL of TMCCAA. Experimental results show a considerable SLL reduction with respect to the uniform case. Again, the results show Case-2 outperforms Case-1 with respect to SLL and directivity. Apart from this, the powers radiated at the center/fundamental frequency, the first two sideband frequencies, and dynamic efficiency have been computed. It has been observed that as the sideband frequency increases, both the powers radiated by harmonic frequencies, sideband level decrease. The aperture size is a very important constraint for the array. Hence, in our optimized design, the maximum radius of the concentric ring array is constrained.