ABSTRACT

In this paper, we propose a technique based on two evolutionary algorithms simulated annealing and particle swarm optimization to design a linear array of half wavelength long parallel dipole antennas that will generate a pencil beam in the horizontal plane with minimum standing wave ratio (SWR) and fixed side lobe level (SLL). Dynamic range ratio of current amplitude distribution is kept at a fixed value. Two different methods have been proposed with different inter-element spacing but with same current amplitude distribution. First one uses a fixed geometry and optimizes the excitation distribution on it. In the second case further reduction of SWR is done via optimization of inter-element spacing while keeping the amplitude distribution same as before. Coupling effect between the elements is analyzed using induced EMF method and minimized in terms of SWR. Numerical results obtained from SA are validated by comparing with results obtained using PSO.