Miniature radiation pattern reconfigurable antenna for 2.4 GHz band

Reconfigurable antennas offer the possibility of changing characteristics over time to maintain a high quality wireless communications link as the propagation environment changes. Radiation pattern reconfigurable antennas are of particular interest because manipulation of the radiation pattern enables avoidance of noise source, improved security by directing signals only toward intended users, avoidance of signal fades, improved beam steering capability of phased array systems, and increased diversity gain [1]. Various designs have been proposed [2] to achieve radiation pattern and frequency reconfiguration. A key design issue for pattern reconfigurable antennas is that antenna dimensions must be electrically small for many wireless applications. Many types of reconfigurable antennas have been demonstrated, but significant pattern change can require electrically large antenna structures. The goal of this work is to achieve pattern reconfigurability with a compact, electrically small, low cost planar antenna design. We report on a reconfigurable antenna design that achieves these performance criteria for the ISM band. The antenna was simultaneously optimized for small size, low return loss, and high pattern reconfigurability.