Analysis of dual-band non-uniformly spaced arrays for mobile communications

This paper presents an analysis of a dual-band array for base stations of mobile communication systems. The main challenge is to suppress grating lobes for interelement spacings equal or larger than the wavelength. In order to achieve this result, particle swarm optimization (PSO) is used to find the optimum excitation coefficients (amplitudes and phases) and the non-uniform spacing between elements of the array. The suppression of grating lobes is shown by comparisons with results obtained with a standard uniform linear array for two cases: standard beam pointing to the boresight, and main beam with squared cosecant shape. The use of non-uniform spaced arrays allowed reducing grating lobes in comparison to a standard uniform array.