Non-Foster Enhancements of electrically small antennas

Various attributes of metamaterials have led to their consideration for engineering metamaterial-inspired structures for a variety of applications. This includes the miniaturization of resonators and their use for improving the performance characteristics of electrically small antennas from the microwave region up through to the optical region. Achieving higher directivity from electrically small antennas by introducing structured ground planes has been considered successfully. Active metamaterial constructs have been introduced to increase the bandwidths at low frequencies and to overcome the losses at high frequencies. They have led to recent non-Foster antenna designs and experiments. Thus the development of an efficient, high directivity, large bandwidth electrically small antenna is rapidly becoming a possibility.