Comparative performance of QPSO and BSA for design of linear array of parallel dipole antennas with mutual coupling

Abstract

The authors presented two different optimization methods-one is quantum particle swarm optimization (QPSO) and another is backtracking search algorithm (BSA). Combined with inverse fast fourier transform (IFFT), the paper deals with the synthesis of array of linearly spaced and mutually coupled half wavelength very thin vertical and parallel dipoles with fixed value of voltage standing wave ratio (VSWR) and side lobe level. The performances of the two algorithms are compared in terms of different antenna parameters like side lobe level, VSWR as well as statistical parameters such as best fitness value, mean, standard deviation and computation time. There exists mutual coupling among the parallel half-wavelength dipole antennas. Self and mutual impedances are derived from induced EMF method assuming distribution of current on each dipole is sinusoidal. The pattern so generated is broadside in the horizontal plane. There exists a relationship between the IFFT and the array factor for an array of linearly and uniformly spaced isotropic antennas. Array factor is found out by applying inverse fast fourier transform on the element excitations that in turn reduces the computational time. It is assumed that the element pattern of vertical half-wavelength dipole antenna is omni-directional in the horizontal plane. One example is presented to prove the effective use of the approach proposed.