Physical Insight into the 'Growing' Evanescent Fields of Double-Negative Metamaterial Lenses Using their Circuit Equivalence

Pendry in his paper [Phys. Rev. Lett., 85, 3966 (2000)] put forward an idea for a lens made of a lossless metamaterial slab with n = -1, that may provide focusing with resolution beyond the conventional limit. In his analysis, the evanescent wave inside such a lossless double-negative (DNG) slab is 'growing', and thus it 'compensates' the decaying exponential outside of it, providing the sub-wavelength lensing properties of this system. Here, we examine this debated issue of 'growing exponential' from an equivalent circuit viewpoint by analyzing a set of distributed-circuit elements representing evanescent wave interaction with a lossless slab of DNG medium. Our analysis shows that, under certain conditions, the current in series elements and the voltage at the element nodes may attain the dominant increasing due to the suitable resonance of the lossless circuit, providing an alternative physical explanation for 'growing exponential' in Pendry's lens and similar sub-wavelength imaging systems.Comment: 7 pages, 2 figures, 1 table, submitted to IEEE Transactions on Antennas and Propagatio

'Growing Evanescent Envelopes and Anomalous Tunneling' in Cascaded Sets of Frequency-Selective Surfaces in Their Stop Bands

The presence of wave tunneling and the 'growing evanescent envelope' for field distributions in suitably designed, periodically layered stacks of frequency selective surfaces (FSS) is discussed in this paper. Here it is shown that a setup completely different completely different from the Pendry's lens allows an analogous buildup of evanescently modulated waves. In particular, it is shown how an interface resonance phenomenon similar to the one present at the interface between metamaterials with oppositely signed constitutive parameters may be induced by a proper choice of the periodicities of the FSS stacks and the geometrical properties of these surfaces. The analysis is performed through an equivalent transmission-line approach, and some physical insights into this phenomenon are presented. Salient features, such as the complete wave tunneling through the pair of cascaded FSS, each operating at its bandgap, are presented and discussed.Comment: 5 pages, 2 figures, submitted to Physical review

Metamaterials with Negative Permittivity and Permeability: Background, Salient Features, and New Trends

Here we first present a brief background and the history of complex media, in particular the materials with negative permittivity and permeability, and then we discuss some of the salient electromagnetic features of these metamaterials. This is followed by description of some of the ideas regarding potential future applications of these metamaterials in devices and components, along with physical remarks and intuitive justification

An Idea for Thin Subwavelength Cavity Resonators Using Metamaterials With Negative Permittivity and Permeability

In this letter, we present and analyze theoretically some ideas for thin one-dimensional (1-D) cavity resonators in which a combination of a conventional dielectric material and a metamaterial possessing negative permittivity and permeability has been inserted. In this analysis, it is shown that a slab of metamaterial with negative permittivity and permeability can act as a phase compensator/conjugator and, thus, by combining such a slab with another slab made of a conventional dielectric material one can, in principle, have a 1-D cavity resonator whose dispersion relation may not depend on the sum of thicknesses of the interior materials filling this cavity, but instead it depends on the ratio of these thicknesses. In other words, one can, in principle, conceptualize a 1-D cavity resonator with the total thickness far less than the conventional λ/2. Mathematical steps and physical intuitions relevant to this problem are presented