Modulation patterns for surface scattering antennas

Patent metadata

Field	Value
Publication number	US-9812779-B2
Application number	US-201615010165-A
Country	US
Kind code	B2
Filing date	Jan 29, 2016
Priority date	Jun 20, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Modulation patterns for surface scattering antennas provide desired antenna pattern attributes such as reduced side lobes and reduced grating lobes.

First claim

What is claimed is:

1. A method, comprising:
discretizing a hologram function for a surface scattering antenna that defines an aperture, where the discretizing includes
identifying a discrete plurality of locations on the aperture for a discrete plurality of scattering elements of the surface scattering antenna and
identifying a discrete set of states for each of the scattering elements corresponding to a discrete set of function values at each of the locations of the scattering elements; and

identifying an antenna configuration that reduces artifacts attributable to the discretizing,
wherein the identifying of the antenna configuration includes altering a Fourier spectrum of the discretized hologram function.

2. The method of claim 1 , further comprising:
adjusting the surface scattering antenna to the identified antenna configuration.

3. The method of claim 1 , further comprising:
operating the surface scattering antenna in the identified antenna configuration.

4. The method of claim 1 , further comprising:
storing the identified antenna configuration in a storage medium.

5. The method of claim 1 , wherein the altering of the Fourier spectrum of the discretized hologram function includes, for each location in the plurality of scattering locations:
identifying a first contribution of the location to one or more desired spatial Fourier components of the discretized hologram function;
identifying a second contribution of the location to one or more undesired spatial Fourier components of the discretized hologram function; and
selecting a function value for the location from the discrete set of functions values, where the selected value equals:
a value in the discrete set of function values that is closest to the hologram function evaluated at the location, if the ratio of the first contribution to the second contribution is greater than a selected amount;

or
a minimum value in the discrete set of function value, if the ratio of the first contribution to the second contribution is less than or equal to a selected amount.

6. The method of claim 5 , wherein the one or more desired spatial Fourier components are fundamental spatial Fourier components of the discretized hologram function.

7. The method of claim 5 , wherein the one or more undesired spatial Fourier components include a harmonic spatial Fourier component of the discretized hologram at a non-evanescent spatial frequency.

8. The method of claim 5 , wherein the one or more undesired spatial Fourier components include a harmonic spatial Fourier component of the discretized hologram at a evanescent spatial frequency that is aliased to a non-evanescent spatial frequency by the discretizing of the discrete plurality of locations.

9. The method of claim 5 , wherein the identifying of the antenna configuration includes, for each scattering element in the plurality of scattering elements:
identifying a state for the scattering element selected from the discrete set of states and corresponding to the selected function value for the location of the scattering element.

10. The method of claim 1 , wherein the altering of the Fourier spectrum of the discretized hologram function includes:
altering the hologram function by replacing a fundamental spatial Fourier component of the hologram function with a plurality of spatial Fourier components.

11. The method of claim 10 , wherein the plurality of spatial Fourier components is a discrete set of Fourier components within a selected spatial frequency bandwidth around a fundamental spatial frequency corresponding to the fundamental spatial Fourier component.

12. The method of claim 10 , wherein the plurality of spatial Fourier components is a continuous spectrum of Fourier components within a selected spatial frequency bandwidth around a fundamental spatial frequency corresponding to the fundamental spatial Fourier component.

13. The method of claim 1 , wherein the altering of the Fourier spectrum of the discretized hologram function includes:
altering the discretized hologram function by selectively reducing a harmonic spatial Fourier component of the discretized hologram function.

14. The method of claim 13 , wherein the selectively reducing includes selectively eliminating the harmonic spatial Fourier component.

15. The method of claim 13 , wherein the selectively-reduced harmonic spatial Fourier component is a harmonic spatial Fourier component at a non-evanescent spatial frequency.

16. The method of claim 13 , wherein the selectively-reduced harmonic spatial Fourier component is a harmonic spatial Fourier component at a evanescent spatial frequency that is aliased to a non-evanescent spatial frequency by the discretizing of the discrete plurality of locations.

17. A system, comprising:
a surface scattering antenna with a plurality of adjustable scattering elements that are adjustable between a discrete set of states corresponding to a discrete set of function values at each location in a plurality of locations for the plurality of adjustable scattering elements;
a storage medium on which a set of antenna configurations corresponding to a set of hologram functions is written, each antenna configuration being selected to reduce artifacts attributable to a discretization of the respective hologram function; and
control circuitry operable to read antenna configurations from the storage medium and adjust the plurality of adjustable scattering elements to provide the antenna configurations;
wherein at least one antenna configuration is a Fourier-spectrum-altered discretization of the respective hologram function.

18. The system of claim 17 , wherein the adjustable scattering elements are adjustable between a discrete set of states including a minimum state, and the Fourier-spectrum-altered discretization of the respective hologram function includes one or more scattering elements set to the minimum state to reduce their disproportional contribution to one or more undesired spatial Fourier components of the discretization of the respective hologram function.

19. The system of claim 18 , wherein the one or more undesired spatial Fourier components include a harmonic spatial Fourier component of the discretization at a non-evanescent spatial frequency.

20. The system of claim 18 , wherein the one or more undesired spatial Fourier components include a harmonic spatial Fourier component of the discretization at an evanescent spatial frequency that is aliased to a non-evanescent spatial frequency by the discretization.

21. The system of claim 17 , wherein the Fourier-spectrum-altered discretization of the respective hologram function is a discretization of an altered hologram function that replaces a fundamental spatial Fourier component of the respective hologram function with a plurality of spatial Fourier components.

22. The system of claim 21 , wherein the plurality of spatial Fourier components is a discrete set of Fourier components within a selected spatial frequency bandwidth around a fundamental spatial frequency corresponding to the fundamental spatial Fourier component.

23. The system of claim 21 , wherein the plurality of spatial Fourier components is a continuous spectrum of Fourier components within a selected spatial frequency bandwidth around a fundamental spatial frequency corresponding to the fundamental spatial Fourier component.

24. The system of claim 17 , wherein the Fourier-spectrum-altered discreti

Assignees

• Searete Llc
• The Invent Science Fund I Llc

Inventors

• Chen Pai-Yen
• Driscoll Tom
• Ebadi Siamak
• Hunt John Desmond
• Landy Nathan Ingle
• Machado Melroy
• Perque Jr Milton
• Smith David R
• Urzhumov Yaroslav A

Classifications

• H01Q11/02

  Non-resonant antennas, e.g. travelling-wave antenna (Yagi antennas H01Q19/30) · CPC title

• H01Q13/20 Primary

  Non-resonant leaky-waveguide or transmission-line antennas; Equivalent structures causing radiation along the transmission path of a guided wave · CPC title

• H01Q3/44 Primary

  varying the electric or magnetic characteristics of reflecting, refracting, or diffracting devices associated with the radiating element · CPC title