The invisibility cloak has been drawing much attention due to its new concept for manipulating many physical fields, from oscillating wave fields (electromagnetic, acoustic and elastic) to static magnetic fields, dc electric fields, and diffusive fields. Here, an electrostatic field invisibility cloak has been theoretically investigated and experimentally demonstrated to perfectly hide two dime...

In this paper, a generalization of cloaking is presented: instead of an empty region of space, an inhomogeneous structure is transformed via Pendry's map in order to give, to any object hidden in the central hole of the cloak, a completely arbitrary appearance. In 2006, it was suggested by Pendry et al. [1] that an object surrounded by a coating consisting of an exotic material becomes invisibl...

Introduction An acoustic cloak is a shell surrounding an object so that sound incident from any direction passes through and around the cloak, making the cloak and the object acoustically “invisible.” We do not experience acoustic cloaking because the materials required are exotic and, as far as we know, not found in nature. Yet there is no fundamental physical restriction on acoustic cloaking....

(Phys.org) —Researchers have discovered an alternative way to make an invisibility cloak that departs from other attempts to do so. Attempts in the past have been via metamaterials, created by assembling structures that interact with the light they will cloak. Metamaterials are far from perfect, are expensive, and are time-consuming, so the research team, from Zhejiang University in China, the ...

A recently published theory has suggested that a cloak of invisibility is in principle possible, at least over a narrow frequency band. We describe here the first practical realization of such a cloak; in our demonstration, a copper cylinder was "hidden" inside a cloak constructed according to the previous theoretical prescription. The cloak was constructed with the use of artificially structur...

We describe a novel type of electromagnetic cloak designed to conceal an object in a corner, and demonstrate its excellent performance by employing direct numerical simulation. Furthermore, we study the angular dependence and the effect of loss on the invisibility performance and compare ideal and simplified cloaks. The proposed structure has homogeneous constitutive parameters, which greatly s...

A new, metamaterial-based electromagnetic cloaking operation is proposed in this study. The metamaterial exhibits a sharp transmittance in the C-band of the microwave spectrum with negative effective property of permittivity at that frequency. Two metal arms were placed on an FR-4 substrate to construct a double-split-square shape structure. The size of the resonator was maintained to achieve t...

The ideal transformation optics cloaking is accompanied by shielding: external observations do not provide any indication of the presence of a cloaked object, nor is any information about the fields outside detectable inside the cloaked region. In this paper, a transformation is proposed to cloak three-dimensional objects for electromagnetic waves in sensor mode, i.e., cloaking accompanied by d...

The paper reveals the design of a unit cell of a metamaterial that shows more than 2 GHz wideband near zero refractive index (NZRI) property in the C-band region of microwave spectra. The two arms of the unit cell were splitted in such a way that forms a near-pi-shape structure on epoxy resin fiber (FR-4) substrate material. The reflection and transmission characteristics of the unit cell were ...

The aim of (passive) cloaking with respect to electromagnetic (or acoustic) sensing is to surround a region of space with a material layer – the cloak – that renders its contents and even the existence of the layer undetectable by such measurements. At least theoretically this can be achieved using the coordinate invariance of the underlying wave equation, through so-called cloaking by mapping....