Electrically small metamaterial-inspired antennas: Designs and measurements, efficiency and bandwidth performance

Electrically small antennas are a critical enabling technology for a variety of wireless applications. The usually incompatible demands for electrically small, efficient, and broad bandwidth antenna systems often becomes further acerbated by practical demands of multi-functionality, low weight, low cost, and easy manufacturing. A variety of metamaterial-based and metamaterial-inspired antenna systems have been achieved recently that meet many of these demands. The essential features of these antennas and the experimental validation of their performance, especially their overall efficiencies, as well recent design extensions that have bandwidths near the Chu limit, will be reviewed.