Near-Field Focusing Plates and Their Design

TL;DR

This paper presents a design method for near-field focusing plates that can focus electromagnetic waves to subwavelength spots, demonstrating their effectiveness through simulations and analyzing their robustness against losses.

Contribution

It introduces a general design procedure for near-field plates capable of focusing beyond the diffraction limit at microwave frequencies.

Findings

Successfully focused electromagnetic waves to subwavelength spots.

Designs are robust against material losses.

Simulations confirm the plates' ability to overcome diffraction limits.

Abstract

This paper describes the design of near-field focusing plates, which are grating-like structures that can focus electromagnetic radiation to spots or lines of arbitrarily small subwavelength dimension. A general procedure is outlined for designing a near-field plate given a desired image, and its implementation at microwave frequencies is discussed. Full-wave (method of moments) simulations clearly demonstrate the near-field plate's ability to overcome the diffraction limit. Finally, it is shown that the performance of near-field plates is weakly affected by losses.