A variety of passive metamaterial properties have been used to enhance the performance of radiating and scattering systems. These include artificial magnetic conductors for low profile antennas, zero-index superstrates for highly directive antennas, efficient electrically small antennas, and dispersion-engineered pulse-driven antennas. Active metamaterials have been introduced to enhance the bandwidth properties of the efficient electrically small radiators and to overcome material losses in the optical regime to achieve electrically small optical lasers and amplifiers.
Several of these systems will be reviewed – from a practical point of view. In particular, the differences between the often theoretical metamaterial-based designs and the realized metamaterial-inspired designs will be emphasized. The theoretical basis for the designs will be reviewed. The modeling techniques used to simulate the designs and to guide the fabrication and experimental testing of them will be discussed. Experimental confirmation of the metamaterial-engineering design paradigms introduced by these efforts will be used to highlight the practical points of interest.