Asymmetrical radiation pattern synthesis of a linear array antenna by a least mean square method

In mobile base station antennas, linear array antennas are employing and asymmetrical radiation patterns are achieved. For multi frequency use, unequally spaced array configurations are preferable because of reducing grating lobes in higher frequency operations. Previously, radiation pattern synthesis methods were developed for equally spaced array configurations. In radiation pattern synthesis method, the least mean square (LMS) method was very conveniently used in mobile base station designing. The convenience of this method is obtaining array excitation coefficients by simply giving the objective radiation pattern. Moreover, the merit of this method is having the function of emphasizing design importance in the radiation angles that is called the weighting matrix. In this paper, a radiation pattern synthesis program based on LMS scheme is developed for unequally spaced array configuration. As an initial step, the accuracies of a developed program are examined. Through designing actual asymmetric radiation pattern with very low side lobe levels, the accuracies of program and effects of weighting matrix are ensured.