Adaptive antenna arrays have been used on military applications for quite sometime. In the next century, they will find their way into commercial systems in ways that are cost effective and yield robust performance. Future uses for smart antennas will include transmit base stations and terminals. Especially challenging is the handheld radio in the presence of severe multipath and blockage of the line of sight path by objects. Although there is very little space on a handheld radio, it turns out that considerable reliability improvement can be realized using spatial diversity with two separate antennas on the radio.
Processing can be simple switched diversity or adaptive beam steering and null steering.
In addition to space diversity, polarization and pattern diversity are also very promising. With the increase in wireless services will come an increase in the number of functions for a single antenna. This will occur in all levels of systems, ranging from handheld radios to battleships. On the handheld level, multifunctional antennas are needed for multimode radios. Today dual mode radios are being manufactured for use with both satellite and terrestrial communications.