Nonradiating and radiating configurations driven by left-handed metamaterials

It is shown that a pair of identical emitters (e.g., wire dipole antennas) in the focal points of a disk, made of left-handed metamaterial (a perfect lens), forms a nonradiating electromagnetic configuration. The emitters are fed with voltages of equal magnitude and pi out of phase. Detailed finite-difference time-domain modeling shows that nonpropagating electromagnetic fields are generated—fields that remain confined within the region between the emitters and the lens. The energy balance of the system shows that the radiation resistance of the system is low. This means that the input power is converted into heat in the volume of the lens, and only a small fraction of it is radiated. The system performance shows that disturbing the configuration of the nonpropagating electromagnetic fields with the presence of an externally introduced object stimulates radiation. This suggests possible detector applications. In-phase feeding voltages are also studied with the consequence that the radiation resistance of the antennas is increased.