Electromagnetic beam steering antenna

Patent metadata

Field	Value
Publication number	US-9748644-B2
Application number	US-201715397884-A
Country	US
Kind code	B2
Filing date	Jan 4, 2017
Priority date	Jul 20, 2015
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

Described embodiments include an electromagnetic beam steering apparatus. The apparatus includes a first blazed transmission diffraction grating component configured to angularly deflect an electromagnetic beam at a first blaze angle. The apparatus includes a second blazed transmission diffraction grating component configured to angularly deflect an electromagnetic beam at a second blaze angle. The apparatus includes an electromagnetic beam steering structure configured to independently rotate the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component about a coaxial axis such that an electromagnetic beam incident on the first blazed transmission diffraction grating component exits the second blazed transmission diffraction grating component as a steered electromagnetic beam.

First claim

What is claimed is:

1. An electromagnetic beam steering apparatus comprising:
a first blazed transmission diffraction grating component having a first volumetric distribution of dielectric constants configured to angularly deflect an electromagnetic beam at a first blaze angle;
a second blazed transmission diffraction grating component having a second volumetric distribution of dielectric constants configured to angularly deflect the electromagnetic beam at a second blaze angle; and
an electromagnetic beam steering structure configured to independently rotate the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component about a coaxial axis such that an electromagnetic beam incident on the first blazed transmission diffraction grating component exits the second blazed transmission diffraction grating component as a steered electromagnetic beam.

2. The apparatus of claim 1 , wherein the first volumetric distribution of dielectric constants is divided into a plurality of sub-wavelength voxels having a maximum dimension of less than half of a wavelength of the electromagnetic beam, and each voxel is assigned one of a plurality of dielectric constants to approximate the first volumetric distribution of dielectric constants.

3. The apparatus of claim 1 , wherein the first volumetric distribution of dielectric constants is approximated using one or more discrete materials having specific dielectric constants.

4. The apparatus of claim 1 , wherein the second volumetric distribution of dielectric constants is divided into a plurality of sub-wavelength voxels having a maximum dimension of less than half of a wavelength of the electromagnetic beam, and each voxel is assigned one of a plurality of dielectric constants to approximate the second volumetric distribution of dielectric constants.

5. The apparatus of claim 1 , wherein the second volumetric distribution of dielectric constants is approximated using one or more discrete materials having specific dielectric constants.

6. The apparatus of claim 1 , wherein the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component have substantially similar volumetric distribution of dielectric constants.

7. The apparatus of claim 1 , wherein the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component have dissimilar volumetric distributions of dielectric constants.

8. The apparatus of claim 1 , wherein the first volumetric distribution of dielectric constants is selected based on an equation for a holographic solution.

9. The apparatus of claim 1 , wherein the first volumetric distribution of dielectric constants is selected using an optimization algorithm in which the dielectric constants are treated as optimizable variables.

10. The apparatus of claim 9 , wherein the real and imaginary parts of the dielectric constants are treated as individually optimizable variables.

11. The apparatus of claim 9 , wherein the optimization algorithm includes modifying at least one optimizable variable and determining a cost function for the modification.

12. The apparatus of claim 9 , wherein the optimization algorithm includes determining a gradient of the cost function based on its partial derivatives with respect to each optimizable variable.

13. The apparatus of claim 9 , wherein the optimization algorithm includes determining a sensitivity vector of a given configuration using an adjoint sensitivity algorithm.

14. The apparatus of claim 9 , wherein the optimization algorithm comprises a constrained optimization algorithm in which the dielectric constants are treated as optimization variables constrained to have real parts greater than or equal to approximately one and imaginary parts equal to or approximately zero.

15. The apparatus of claim 9 , wherein the optimization algorithm includes starting with an initial guess corresponding to a holographic solution.

16. The apparatus of claim 1 , wherein the electromagnetic beam steering structure includes an electronically controlled electromagnetic beam steering structure.

17. The apparatus of claim 1 , wherein the electromagnetic beam steering structure is configured to independently rotate or counter rotate the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component relative to the coaxial axis.

18. The apparatus of claim 1 , wherein the electromagnetic beam steering structure is configured to rotate the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component about the coaxial axis while maintaining an electromagnetic beam path through the first blazed transmission diffraction grating component and the second blazed transmission diffraction grating component.

19. The apparatus of claim 1 , further comprising:
a beam controller configured to calculate a rotational position of the first blazed transmission diffraction grating component about the coaxial axis and a rotational position of the second blazed transmission diffraction grating component about the coaxial axis pointing the steered electromagnetic beam at a selected target.

20. The apparatus of claim 1 , further comprising:
an electromagnetic beam generator configured to transmit the electromagnetic beam.

21. A method comprising:
passing an electromagnetic beam through a first blazed transmission diffraction grating component having a first volumetric distribution of dielectric constants configured to angularly deflect the electromagnetic beam at a first blaze angle relative to a coaxial axis and generating a first output electromagnetic beam; and
passing the first output electromagnetic beam through a second blazed transmission diffraction grating component having a second volumetric distribution of dielectric constants configured to angularly deflect the first output electromagnetic beam at a second blaze angle relative to the coaxial axis and generating a steered electromagnetic beam;
the steered electromagnetic beam having a direction relative to the coaxial axis that is a vector sum of the first blaze angle and the second blaze angle.

22. The method of claim 21 , wherein the first volumetric distribution of dielectric constants divided into a plurality of sub-wavelength voxels having a maximum dimension of less than half of the wavelength of the electromagnetic beam, and each voxel assigned one of a plurality of dielectric constants to approximate the first volumetric distribution of dielectric constants.

23. The method of claim 21 , wherein the second volumetric distribution of dielectric constants divided into a plurality of sub-wavelength voxels having a maximum dimension of less than half of a wavelength of the electromagnetic beam frequency, and each voxel assigned one of a plurality of dielectric constants to approximate the second volumetric distribution of dielectric constants.

24. The method of claim 21 , further comprising:
rotating the first blazed transmission diffraction grating component around the coaxial axis to a first selected position; and
rotating the second blazed transmission diffraction grating component around the coaxial axis to a second selected position;
wherein the steered electromagnetic beam has an azimuth angle θ and a zenith angle φ between zero and a finite

Assignees

• Elwha Llc

Inventors

• Driscoll Tom
• Hyde Roderick A
• Ishikawa Muriel Y
• Kare Jordin T
• Myhrvold Nathan P
• Pan Tony S
• Tegreene Clarence T
• Urzhumov Yaroslav A
• Wood Jr Lowell L
• Wood Victoria Y H

Classifications

• G02F2203/24

  beam steering · CPC title

• G02B26/0808

  by means of one or more diffracting elements · CPC title

• H01Q15/02

  Refracting or diffracting devices, e.g. lens, prism · CPC title

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• H01Q3/14 Primary

  for varying the relative position of primary active element and a refracting or diffracting device · CPC title