The development of smart antennas

A smart or adaptive antenna is an antenna that modifies its receive or transmit characteristics in order to enhance the antenna's performance. The performance modification results from purposely modifying the signal cancellations that occur. Smart antennas are important for reducing the deleterious effects of intentional jamming signals, unintentional co-channel interference and multipath. These antennas were first known as sidelobe cancelers then adaptive antennas and more recently smart antennas. A smart antenna is composed of two or more antennas. The amplitude and/or time delay (phase) of the signals received by all the antennas are modified then combined in such a manner as to improve reception of the desired signal. This paper presents the development of smart antennas from sidelobe cancelers in the 1950s until today.