Planar magnetoinductive lens for three-dimensional subwavelength imaging

Abstract

A planar near-field magnetoinductive lens operating in the microwave range is presented. The proposed device consists of two parallel planar arrays of metallic broadside coupled (BC) split-ring resonators (SRRs), or BC-SRRs. The power coming from a point-like source located in front of the lens is focused into a receiver located in free space beyond the lens. This focus is clearly separated from the back side of the lens, and has a size that is an order of magnitude smaller than the free space wavelength of the incoming field. The imaging properties of the device relies mainly on the excitation of magnetoinductive surface waves on the BC-SRR arrays. By simply scaling the BC-SRRs’ size, as well as the arrays periodicity, the operation frequency of the device can be tuned in a wide frequency range. Thus, the proposed design is potentially useful for many applications ranging from megahertz to terahertz.