Tailoring of the subwavelength focus

Subwavelength focusing by an ensemble of magnetically coupled metamaterial elements is studied theoretically for the case when all the dimensions are small relative to the electromagnetic wavelength. It is shown that in contrast to expectation a focus can be placed in any desired position for any transmitter-lens configuration by the appropriate tuning of the receiver. A mathematical proof is provided and two examples are shown demonstrating a focal width of lambda/60. (C) 2007 Wiley Periodicals, Inc.