Broad band invisibility cloak made of normal dielectric multilayer

Abstract

We present the design, fabrication and performance test of a quasi three-dimensional carpet cloak made of normal dielectric in the microwave regime. Taking advantage of a simple linear coordinate transformation we design a carpet cloak with homogeneous anisotropic medium and then practically realize the device with multilayer of alternating normal dielectric slabs based on the effective medium theory. As a proof-of-concept example, we fabricate the carpet cloak with multilayer of FR4 dielectric slabs with air spacing. The performance of the fabricated design is verified through full-wave numerical simulation and measurement of the far-field scattering electromagnetic waves in a microwave anechoic chamber. Experimental results have demonstrated pronounced cloaking effect in a very broad band from 8 GHz to 18 GHz (whole X and Ku band) due to the low loss, non-dispersive feature of the multilayer dielectric structure.Comment: 10 pages, 4 figures. Accepted in Appl. Phys. Let

Designing retrodirective reflector on a planar surface by transformation optics

“…Such simple design allows us to further realize the retrodirective reflector by alternating layers of normal dielectrics based on the effective medium a Corresponding author, email: yjfeng@nju.edu.cn theory. [18][19][20] The proposal and the practical designs have been verified by full wave EM simulations, which indicate that the retrodirective reflector can be easily realized by multilayer of normal dielectrics, but the thickness and practical realization may be limited by the requirement of high value of dielectric permittivity.…”

“…19,20 The method is based on the effective medium theory (EMT), 21 through which the birefringent dielectric can be represented by multilayer of alternating isotropic dielectric 1 and dielectric 2 (as indicated schematically in Fig. 1(c)).…”

Towards omnidirectional, large scale, full polarization, and broadband practical invisibility cloaks: challenges and progress

“…(c) An optical carpet cloak composed of multilayers [65]. (d) A microwave carpet cloak composed of mutlilayers [66].…”

“…The other approach is to use the artificial materials composed of multilayers of two isotropic materials with different permittivities, which is according to the effective medium theory. Based on this method, an optical carpet cloak has been implemented with uniform silicon grating structures (Figure 7c) [63][64][65]; while its microwave counterpart has been implemented with multilayer of FR4 dielectric slabs with air spacing (Figure 7d) [66].…”

A New Invisible Cloak with Broad Stealth Angle Based on Isotropic Material

“…The cloaks include three types, cylindrical3-5, spherical1 and carpet cloak [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Since the first experimental demonstration of the cylindrical cloak on 2006 [3], it is difficult to achieve an isolated invisibility cloak because of the extreme values of the materials and the spatially dependent anisotropic parameters.…”