RADIATION ENHANCEMENT AND RADIATION SUPPRESSION BY A LEFT-HANDED METAMATERIAL

摘要

The perfect lens property of a dispersive and lossy lefthanded metamaterial disk is exploited to superimpose a source of electromagnetic radiation onto its mirror image, formed as a result of reflection from a perfect electric conductor or a perfect magnetic conductor. The superposition of a vertical wire-dipole antenna with its perfect electric conductor image results in an increase of the radiation resistance of the antenna compared with that of an antenna emitting in free space. On the other hand, if the same antenna is coupled to a perfect magnetic conductor image, it is shown that the result is the formation of a nonradiating configuration. The finite-difference time-domain analysis is performed, and this allows a detailed characterization of the systems. It is shown that the nonradiating system allows relatively large amounts of electromagnetic energy to be stored in the left-handed metamaterial disk and that is indicative of strong electromagnetic fields inside the material. This property is employed in a second-harmonic generation process and the potential of a nonradiating configuration as an efficient nonlinear device is demonstrated.