In this paper, a linear phased array is synthesized to produce a desired far field radiation pattern with a constraint on sidelobe level and beamwidth. The amplitude of the excitation current of each individual array element is optimized to give desired sidelobe level and beamwidth. A modified particle swarm optimization (PSO) algorithm with a novel inertial weight variation function and modified stochastic variables is used here. The performance of the modified PSO is compared with standard PSO in terms of amount of iterations required to get desired fitness value and convergence rate. Using optimized excitation amplitudes, the far field radiation pattern of the phased array is analyzed to verify whether the design criterions are satisfied.

Abstract-In this paper, an approximate closed-form expression of the electric field of a conical horn with linear flare is formulated. Copolarization and cross polarization component of the electric field are calculated from the spherical field components using Ludwig's third definition of copolarization and cross polarization. The calculated field expression is found to be in close agreement with experimental results found in literature. The radiation characteristics of the conical horn are analyzed using the derived field expressions.Index Terms-Conical horn antenna, copolarization and cross polarization.