Coating for the concealment of objects from the electromagnetic radiation of antennas

Patent metadata

Field	Value
Publication number	US-11381002-B2
Application number	US-201716342616-A
Country	US
Kind code	B2
Filing date	Oct 24, 2017
Priority date	Oct 24, 2016
Publication date	Jul 5, 2022
Grant date	Jul 5, 2022

Abstract

An assembly comprising a device and an obstacle subjected to an incident electromagnetic wave of wavelength λ. The obstacle is formed from an electrically conductive material and has a substantially cylindrical shape of transverse dimensions r with respect to a longitudinal axis (O, ez). The longitudinal axis is substantially perpendicular to a propagation direction of the incident electromagnetic wave. The obstacle further has a maximum transverse dimension d such that the ration λ/d is less than 1. The device is placed on all or a part of a surface of the obstacle and comprises a sleeve with a dielectric coating of equivalent relative permittivity EREQ, of height hP along a longitudinal axis of the sleeve, substantially equal to formula A, and a sleeve with an electrically conductive coating placed on the periphery of the dielectric coating.

First claim

The invention claimed is:

1. An assembly comprising an obstacle and a device, intended to be subjected to an incident electromagnetic wave of wavelength λ, wherein:
the obstacle is formed of an electrically conductive material and takes a substantially cylindrical shape of longitudinal axis (O; ez), which longitudinal axis is substantially perpendicular to a direction of propagation of the incident electromagnetic wave, said obstacle furthermore having a maximum transverse dimension d such that the ratio d/λ is less than 1;
the device is placed over all or part of a surface of the obstacle so as to decrease a radar cross section of said obstacle, and includes:
a sleeve of a dielectric coating, of equivalent relative dielectric permittivity εreq, of height hp, along a longitudinal axis of said sleeve, which is substantially equal to

λ

2
⁢

ɛ
req

;

a sleeve of an electrically conductive coating placed around the periphery of the dielectric coating, of the same height hp along a longitudinal axis of said sleeve as the height of the dielectric coating sleeve.

2. The assembly as claimed in claim 1 , wherein the dielectric coating is formed of a single dielectric material.

3. The assembly as claimed in claim 1 , wherein the dielectric coating includes a plurality of dielectric materials, a relative dielectric permittivity and a thickness of each of the component dielectric materials of said coating determining the equivalent relative dielectric permittivity εreq.

4. The assembly as claimed in claim 1 , wherein the height hp of the dielectric coating is optimized by means of direct electromagnetic simulation so as to adjust said height for the purpose of seeking a minimum radar cross section for the obstacle.

5. The assembly as claimed in claim 1 , wherein a thickness of the dielectric coating is optimized by means of direct electromagnetic simulation to adjust said thickness for the purpose of seeking a minimum radar cross section for the obstacle.

6. The assembly as claimed in claim 1 , wherein:
the obstacle is an elliptical cylinder;
the dielectric coating and the electrically conductive coating substantially take the shape of elliptical cylindrical sleeves; and
the dielectric coating is adjusted to fit the obstacle and the conductive coating is adjusted to fit the sleeve of said dielectric coating.

7. The assembly as claimed in claim 6 , wherein the generatrix ellipse of the obstacle is a circle and wherein the dielectric coating and the electrically conductive coating substantially take the shape of circular cylindrical sleeves.

8. The assembly as claimed in claim 1 , wherein the obstacle, the dielectric coating and the conductive coating are slightly incurved.

9. The assembly as claimed in claim 1 , wherein at least one of the obstacle or the electrically conductive coating comprise metals.

10. A vehicle including an assembly as claimed in claim 1 .

11. The vehicle according to claim 10 comprising at least one of a sea vehicle, an air vehicle or a land vehicle.

Assignees

• Airbus
• Airbus Sas

Inventors

• Piau Gérard-Pascal
• De Lustrac André
• Borissov Tatiana

Classifications

• H01Q19/021

  Means for reducing undesirable effects · CPC title

• H01Q1/38

  formed by a conductive layer on an insulating support {(patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface  H01Q15/142)} · CPC title

• H01Q1/3233

  particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems · CPC title

• H01Q1/52 Primary

  Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure (absorbing means H01Q17/00) · CPC title

• H01Q17/00 Primary

  Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems · CPC title