Smart antennas for wireless systems

In this article we discuss current and future antenna technology for wireless systems and the improvement that smart and adaptive antenna arrays can provide. We describe standard cellular antennas, smart antennas using fixed beams, and adaptive antennas for base stations, as well as antenna technologies for handsets. We show the potential improvement that these antennas can provide, including range extension, multipath diversity, interference suppression, capacity increase, and data rate increase. The issues involved in incorporating these antennas into wireless systems using CDMA, GSM, and IS-136 in different environments, such as rural, suburban, and urban areas, as well as indoors, are described. Theoretical, computer simulation, experimental, and field trial results are also discussed that demonstrate the potential of this technology.