Several Types of Antennas Composed of Microwave Metamaterials

We present a review of several types of microwave antennas made of metamaterials, including the resonant electrically small antennas, metamaterial-substrate patch antennas, metamaterial flat-lens antennas, and Luneburg lens antennas. In particular, we propose a new type of conformal antennas using anisotropic zero-index metamaterials, which have high gains and low sidelobes. Numerical simulations and experimental results show that metamaterials have unique properties to design new antennas with high performance. key words: metamaterials, resonant antennas, metamaterial substrate, gradient index, anisotropic zero index, flat lens, Luneburg lens, high performance