Thin low-loss dielectric coatings for free-space cloaking

Abstract

We report stereolithographic polymer-based fabrication and experimental operation of a microwave X-band cloaking device. The device is a relatively thin (about one wavelength thick) shell of an air dielectric composite, in which the dielectric component has negligible loss and dispersion. In a finite band (9.7–10.1 GHz), the shell eliminates the shadow and strongly suppresses scattering from a conducting cylinder of six-wavelength diameter for TE-polarized free-space plane waves. The device does not require an immersion liquid or conducting ground planes for its operation. The dielectric constant of the polymer is low enough (ϵ 2.45) to suggest that this cloaking technique would be suitable for higher frequency radiation, including visible light.