A Study of Smart Antenna For Wireless Application

Abstract

Smart antenna is a next generation antenna which can increase capacityin a cellular communication system, can reduce the effect of the multipath fading, increase the diversity gain, and suppress the co-channel interference between different devices. The antenna operates in conjunction with mobile subscriber unit and provides a plurality of antenna elements. The antenna array creates a beamformer for signals to be transmitted from the mobile subscriber unit, and a directional receiving array to more optimally detect and receive signals transmitted from the base station. By directionally receiving and transmitting signals, multipath fading is greatly reduced as well as intercell interference. In this antenna system at least  one active antenna element is active and essentially centrally located within multiple passive antenna elements. The passive antenna elements are coupled to selectable impedance components. Through proper control of the passive antenna element, the cellular communication system directs an antenna beam pattern  towards an antenna tower of a base station to maximize gain, and consequently, single-to-noise ratio thus ,optimum reception is achieved, for example an idle mode which  receives a pilot signal.