One of the most rapidly developing areas of communication is smart antenna systems. With the fast growth of wireless communication in recent years smart antennas attract much attention.These smart antennas gain much attention over the last few years for its ability to significantly increase the performance of wireless systems.An antenna element is not smart by itself,it combines multiple antenna elements with a signal processing capability to optimize its radiation pattern automatically in response to the signal environment. smart antennas have the capacity to improve system performance in terms of capacity,increasing data speed and let mobile telephones operates on less power. smart antennas have many functions like beamforming, interference nulling.beamforming is a method to create the radiation pattern of the antenna array by adding constructively the phases of the signals in the required direction of targets/mobiles.
The smart antenna system estimates the direction of arrival of the signal using technique such as “Multiple Signal Classification”. These smart antennas are of two types, first one is “phased array antenna”, which are used for point to point wireless systems and the second type is “adaptive array antenna” ,these are used for indoor systems. Coming to its applications these smart antennas are mostly used in time division multiple access,4G telephony systems, cellular wireless communications, space applications ,radio astronomy, satellite systems.