Indian Journal of Science and Technology

Abstract

An antenna array consists of antenna elements whose outputs are added in such a way that the parameters of communication system are optimized. As smart antenna is an array system aided by some intelligent algorithm designed to adapt to ­changes in signal environments. Smart antennas offer low co-channel interference and large antenna gain to the desired signal. smart antenna catered for this purpose is called beam forming smart antenna. Since beam forming is performed in software, forming several beams with the same array is possible by simply reusing the array output. In this context the smart antenna is called as Space Division Multiple Axis (SDMA) smart antenna. The signal received at each antenna element is multiplied by an optimum weight and these products are added to get desired output signal. The weight vector can be calculated using one of the many adaptive algorithms such as Least Mean Square algorithm (LMS), Sample Matrix Inversion algorithm (SMI), Recursive Least Square algorithm (RLS) and their variants. This paper studies how weight ­vector and beam pattern of the smart antenna system are changing for different angles of arrival of desired signal and ­different number of antenna elements in an antenna.