Electromagnetic Metamaterials

摘要

Metamaterials are so-named to recognize and emphasize their purpose, which is to achieve material performance "beyond" the limitations of conventional composites. The holy grail of conventional composite design is to achieve an optimum combination of the constituent's properties without requiring that they react. Success is measured by how close the composite properties are to a volumetric average of those of its constituents. One of the goals of this paper is to outline the strategy of metamaterial design, its hallmark being the exploitation of low dimensional phenomena to extend composite performance. Another is to discuss the generality of the metamaterial strategy, and to illustrate its successful implementation in diverse application areas. It is also shown that ideal electromagnetic composite responses cannot be achieved by implementing designs based on utilizing the prevalent effective media theories. More disturbing is the observation that the deviation of the composite response from the ideal is greatest when the disparity of the constituent properties is largest. Unfortunately, this is the situation of most interest, where a volumetrically averaged response has the greatest practical value. This response can be achieved, however, by utilizing electromagnetic metamaterials design. The rules for this approach are illustrated by the successful design of a laminated electromagnetic composite that possesses some remarkable, and previously unattainable properties-