  In this work, near-field imaging by two strongly coupled arrays of split ring
resonators is analyzed. A simple theoretical model is developed to obtain the
transfer function of the lens. This model shows that magnetoinductive surface
waves (MISWs) play the same role as plasmon-polaritons in negative refractive
slabs. In particular, the model predicts that the image is formed near the
resonant frequency of the rings, between the pass-bands for the two MISW
branches that can be excited in the lens. It also predicts a significant image
enhancement when the distance between the source source and the image plane is
smaller than twice the lens width. The predictions of the theoretical model are
supported by measurements in the radio-frequency range. This suggests the
possibility of using this kind of devices to imaging processes in the megahertz
range, as for example in magnetic resonance imaging.
