Device for electromagnetic wave cloaking

Patent metadata

Field	Value
Publication number	US-9971161-B2
Application number	US-201314428643-A
Country	US
Kind code	B2
Filing date	Mar 10, 2013
Priority date	Mar 10, 2013
Publication date	May 15, 2018
Grant date	May 15, 2018

Abstract

An electromagnetic wave cloaking device is described. The device may include a plurality of first-type dielectric units, a plurality of second-type dielectric units, and a plurality of four kinds of spacers. The dielectric units and the spacers are arranged such that an electromagnetic wave incident into the cloaking device can be refracted within the device and around a cloaking area surrounded by the device.

First claim

What is claimed is:

1. An electromagnetic wave cloaking device having an outer shape of a polygonal prism and surrounding a cloaking area therewithin, the device comprising:
two or more first-type dielectric units each respectively comprising a first isotropic medium of a first refractive index; and
two or more second-type dielectric units each respectively comprising a second isotropic medium of a second refractive index, the first refractive index greater than the second refractive index,
wherein:
each of the two or more first-type dielectric units is disposed adjacent to two of the two or more second-type dielectric units,
each of the two or more second-type dielectric units is disposed adjacent to two of the two or more first-type dielectric units,
each of the first-type dielectric units has an inner surface facing the cloaking area, the inner surfaces of the first-type dielectric units collectively enclosing the cloaking area,
each of the second-type dielectric units has an outer surface opposing the cloaking area, the outer surfaces of the second-type dielectric units collectively forming the outer shape of the polygonal prism,
the first isotropic medium is either solid or fluid,
the second isotropic medium is either solid or fluid,
the first-type dielectric units and the second-type dielectric units are transparent to an electromagnetic waves incident from a background dielectric encompassing the device, and
the first-type dielectric units and the second-type dielectric units are arranged such that the electromagnetic wave incident from the background dielectric into the cloaking device along one of a plurality of preferred incident directions with respect to the device passes through at least two of the first-type dielectric units and at least two of the second-type dielectric units, refracted only at interfaces between the first-type dielectric units and the second-type dielectric units, before exiting the cloaking device without reaching the cloaking area surrounded therewithin.

2. The device of claim 1 , wherein each of the first-type dielectric units is a prism with a cross section in a shape of an isosceles triangle,
the cross section comprising:
a first vertex angle which is a vertex angle of the isosceles triangle;
two first legs which are two equal sides of the isosceles triangle; and
a first base which is a base side of the isosceles triangle; and

the prism having five surfaces, the five surfaces comprising:
a top end;
a bottom end;
two first sidewalls, each of the two first sidewalls having a respective one of the two first legs located thereon; and
a third sidewall on which the first base is located, the third sidewall being the inner surface.

3. The device of claim 2 , wherein each of the second-type dielectric units is a prism with a cross section in a shape of an isosceles triangle,
the cross section comprising:
a second vertex angle which is a vertex angle of the isosceles triangle;
two second legs which are two equal sides of the isosceles triangle; and
a second base which is a base side of the isosceles triangle; and

the prism having five surfaces, the five surfaces comprising:
a top end;
a bottom end;
two second sidewalls, each of the two second sidewalls having a respective one of the two second legs located thereon; and
a fourth sidewall on which the second base is located, the fourth sidewall being the outer surface,

and wherein:
each second-type dielectric unit is arranged between two first-type dielectric units, and vice versa, with each pair of adjacent second sidewall and first sidewall opposing each other, each third sidewall facing the cloaking area, and each fourth sidewall facing the background dielectric.

4. The device of claim 3 , further comprising:
a plurality of second-kind spacers, wherein each of the plurality of second-kind spacers separates a respective pair of opposing second sidewall and first sidewall, and is configured to provide a displacement to the electromagnetic wave.

5. The device of claim 3 , further comprising:
a plurality of first-kind spacers, wherein each of the plurality of first-kind spacers separates a respective one of the fourth sidewalls from the background dielectric, and is configured to provide a displacement to the electromagnetic wave;
a first plurality of fourth-kind spacers, wherein each of the first plurality of fourth-kind spacers separates the top end of a respective one of the second-type dielectric units from the background dielectric; and
a second plurality of fourth-kind spacers, wherein each of the second plurality of fourth-kind spacers separates the bottom end of a respective one of the second-type dielectric units from the background dielectric.

6. The device of claim 5 , further comprising:
a plurality of second-kind spacers, wherein each of the plurality of second-kind spacers separates a respective pair of opposing second sidewall and first sidewall, and is configured to provide a displacement to the electromagnetic wave.

7. The device of claim 6 , wherein:
the device comprises six first-type dielectric units and six second-type dielectric units,
a thickness of each first-kind spacer and a thickness of each second-kind spacer and a length of each first base substantially satisfy equation (1):
w 1 +7.04× w 2 <2 A   (1), and

wherein
the second refractive index and a refractive index of the background dielectric substantially satisfy equation (2):
n BG >n 2nd ≥n BG /1.8  (2),

wherein w 1 represents the thickness of each first-kind spacer, w 2 represents the thickness of each second-kind spacer, A represents the length of each first base, n B , represents the refractive index of the background dielectric, and n 2nd represents the second refractive index.

8. The device of claim 3 , further comprising:
a plurality of third-kind spacers, wherein each of the plurality of third-kind spacers separates a respective one of the third sidewalls from the cloaking area;
a first plurality of fourth-kind spacers, wherein each of the first plurality of fourth-kind spacers separates the top end of a respective one of the first-type dielectric units from the background dielectric; and
a second plurality of fourth-kind spacers, wherein each of the second plurality of fourth-kind spacers separates the bottom end of a respective one of the first-type dielectric units from the background dielectric.

9. The device of claim 8 , further comprising:
a plurality of second-kind spacers, wherein each of the plurality of second-kind spacers separates a respective pair of opposing second sidewall and first sidewall, and is configured to provide a displacement to the electromagnetic wave.

10. The device of claim 9 , further comprising:
a plurality of first-kind spacers, wherein each of the plurality of first-kind spacers separates a respective one of the fourth sidewalls from the background dielectric, and is configured to provide a displacement to the electromagnetic wave;
a third plurality of fourth-kind spacers, wherein each of the third plurality of fourth-kind spacers separates the top end of a respective one of the second-type dielectric units from the background dielectric; and
a fourth plurality of fourth-kind spacers, wherein each of the fourth plurality of fourth-kind spacers separates the bottom end of a respective one of the second-type dielectric units from the background dielectric.

11. The device of claim 3 , wherein:
the device comprises six first-type dielectric units and six second-type dielectric units, and wherein
the plurality of preferred incident directions comprises directions perpendicular to the thir

Assignees

• Univ Zhejiang

Inventors

• Chen Hongsheng
• Zheng Bin
• Zhang Baile

Classifications

• F41H3/00

  Camouflage, i.e. means or methods for concealment or disguise (for vessels B63G8/34, B63G13/02 {; sound camouflage, i.e. simulating gun fire noise, F41A33/04; dummy or decoy targets F41J; chaff per se F41J2/00; ammunition for dispensing chaff F42B5/15, F42B12/70; radar absorbing fabrics H01Q17/005}) · CPC title

• G02B17/04

  using prisms only · CPC title

• H01Q15/08 Primary

  formed of solid dielectric material · CPC title

• G02B5/045

  Prism arrays · CPC title

• G02B27/126 Primary

  The splitting element being a prism or prismatic array, including systems based on total internal reflection · CPC title