Motion-Activated Reconfigurable and Cognitive Radio Antenna Systems

In this letter, we present a new technique to control reconfigurable and cognitive radio antenna systems. For both cases, the control is done by sensing a movement in the antenna surroundings. This surrounding awareness ability is achieved by incorporating an infrared (IR) motion detector with the antenna system. Once a movement is detected, the IR sensor generates a voltage that can be used to activate the biasing network of a reconfiguring element on an antenna structure. This concept is first tested on a varactor-based reconfigurable antenna. Then, a modified version of the circuit is used to control a cognitive radio antenna system that consists of a reconfigurable antenna and a wideband sensing antenna.