Smart antenna: weight calculation and side-lobe reduction by unequal spacing technique

Abstract

This paper is divided into two parts. The first part presents the study of smart antenna beamforming where a single beam is shaped by weighting and summing the antenna outputs. In order to calculate the weight of the array elements, the conventional beam-former (known as delay and sum) has been chosen. Matlab software is used to calculate the weights, and to obtain the array factor of 8 elements linear array antenna. The second part illustrates that, the side-lobe can be reduced by using unequal spacing technique, but the number of elements is remained unchanged. The comparison between symmetric and asymmetric arrangement for unequal spacing is also presented. The results show that by using the symmetrical arrangement, the side-lobe obtained is much better than asymmetrical arrangement. In fact, the side-lobe produced by asymmetrical arrangement is worse than the equal arrangement.