Patent ID: 7009565

Claim:
An apparatus comprising an antenna for operation in a range of frequencies including a resonant frequency f res of the antenna associated with a vacuum wavelength λ res of electromagnetic radiation, the antenna comprising: a) at least one resonator of the kind in which a patterned structure, or a shaped material of negative electric permittivity or magnetic permeability, has maximum spatial extent less than one-half λ res and is effective, at least at f res , for: i) supporting a resonance, and ii) coupling to an external radiation field such that the resonant scattering cross-section of the resonator is at least about 0.3λ res 2 for at least one incident polarization and direction of electromagnetic radiation; and b) a transmission line coupled to the resonator such that when the resonator is driven at f res by a driving signal in the transmission line, such portion of the driving signal as reflects back into the transmission line does so with a return loss of at least 10 dB.