From the site visits and U.S. company workshop, it appears that phased arrays and adaptive arrays are considered and researched about equally. Although some companies studied only one type exclusively, others work both on phased and adaptive arrays.

Phased arrays are mainly being studied for point-to-point wireless systems, e.g., for wireless local loops. They are also being considered for macrocellular base stations. For example, in Europe there is work on using 8-element phased arrays on GSM base stations. In Japan, there is work on using very large phased arrays on satellites, as well as on satellite terminals such as on car tops.

Adaptive arrays are being studied for indoor systems, i.e., systems with wide angular spread where the received signals arrive via widely separated paths where a phased array may not be useful in achieving gain. Also they are being studied in microcells and in some cellular base stations. For example, currently in the TDMA system ANSI-136 adaptive antenna algorithms have been widely deployed commercially in the United States. Also adaptive arrays are being considered on cellular terminals where local scattering causes wide angular spread.

Published: July 2000; WTEC Hyper-Librarian