Subwavelength microwave imaging using an array of parallel conducting wires as a lens

An original realization of a lens capable of transmitting images with subwavelength resolution is proposed. The lens is formed by an array of parallel conducting wires and effectively operates as a telegraph which captures a distribution of the electric field at the front interface of the lens and transmits it to the back side without distortions. This regime of operation is called canalization and is inherent in flat lenses formed by electromagnetic crystals. The theoretical estimations are supported by numerical simulations and experimental verification. The subwavelength resolution of $\lambda ∕15$ and 18% bandwidth of operation are demonstrated at gigahertz frequencies. The proposed lens is capable of transporting subwavelength images without distortion to nearly unlimited distances since the influence of losses to the lens operation is negligibly small.

Figure 1

(Color online) Geometry of the flat lens formed by the wire medium and the source of the form of the letter P. (A) Perspective view. (B) Front view. Parameters: $a=10\mathrm{mm}$, $r=1\mathrm{mm}$, $d=150\mathrm{mm}$, $h=5\mathrm{mm}$, $f=1\mathrm{GHz}$.

Figure 2

(Color online) Distribution of electric field and its absolute value: (A),(C) in the vicinity of the source (at $2.5\mathrm{mm}$ distance from the front interface); (B),(D) in the image plane (at $2.5\mathrm{mm}$ distance from the back interface); (E),(F) in the transverse plane.

Figure 3

(Color online) Photo of wire medium lens used in the experiment.

Figure 4

(Color online) Results of near field scan measurements: absolute values of $x$-, $y$-, and $z$-electric field components and total field in arbitrary units: (A,C,E,G) in the source plane and (B,D,F,H) in the image plane, respectively.