What is an Adaptive Antenna?

An adaptive antenna is type of smart antenna. It's "smart" because it improves on the traditional antenna by adjusting for traffic patterns at a given time to increase signal strength and quality. To adjust for frequency and channel use, the adaptive antenna uses multiple antennas and an algorithm in order to maximize the strength of the signals being sent and received while eliminating, or at least reducing, interference.

To improve signal processing, adaptive antenna systems include several components. Performance monitors and rapid control processors are used to continually assess the radio frequency environment. A complex algorithm is constantly running to identify interferences and differentiate them from the desired signal.

In addition to the monitoring and processing system, this type of antenna uses multiple antennas to improve signal quality. The multiple antennas can be affixed to a base station in a number of patterns, including circular, linear or planar patterns. The multiple antennas are comprised of one main antenna, or lobe as well as other antennas, or nulls. The lobe is actually directed toward the desired signal while the nulls are used to deflect interfering signals. This technique is known as beamforming, beamsteering or beemshaping.

An adaptive antenna can be used both at a base station or at an individual terminal. Having an adaptive antenna both at the source and by the end user would improve the signal although it is likely unnecessary. Determining whether this type of antenna should be employed at the base station or by individual terminals is often an issue primarily of cost. Installing this antenna at the base station would spread the cost of one antenna among many users whereas costs associated with using adaptive antennas by individual terminals would be absorbed by each individual.

Benefits include improved signal quality, increased signal range and coverage, and increased data transfer rates. These benefits, however, depend on the actual circumstances of where this type of antenna is used. For example, complex environments where many radio frequencies are frequently used may counter the benefits provided by an adaptive antenna.