Two-Dimensionally Electronically-Steerable Artificial Impedance Surface Antenna

• US 20150214615A1
• Filed: 04/09/2015
• Published: 07/30/2015
• Est. Priority Date: 11/03/2010
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Patel, Amit M., Quarfoth, Ryan G.
• Granted Patent: US 9,871,293 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01Q 13/28 comprising elements constituting electric discontinuities and spaced in direction of wave propagation, e.g. dielectric elements or conductive elements forming artificial dielectric
• CPC Class Codes: H01Q 15/0066 said selective devices being reconfigurable, tunable or controllable, e.g. using switches
• CPC Class Codes: H01Q 3/36 with variable phase-shifters
• CPC Class Codes: H01Q 3/443 varying the phase velocity along a leaky transmission line frequency scanning H01Q3/22; non-resonant leaky-waveguide or transmission-line aerials H01Q13/20

Abstract

A method and apparatus for electronically steering an antenna system is provided. A surface wave is propagated along each of a number of surface wave channels formed in each of a plurality of radiating elements to form a radiation pattern. Each surface wave channel in the number of surface wave channels formed in each radiating element in the plurality of radiating elements is coupled to a transmission line configured to carry a radio frequency signal using a surface wave feed in a plurality of surface wave feed associated with the plurality of radiating elements. A main lobe of the radiation pattern is electronically steered by controlling voltages applied to a plurality of switch elements connecting a plurality of impedance elements in each of the number of surface wave channels.

Claims

1. An apparatus comprising:

a plurality of radiating elements, wherein each radiating element in the plurality of radiating elements comprises a number of surface wave channels in which each of the number of surface wave channels is configured to constrain a path of a surface wave and comprises;

a plurality of switch elements; and

a plurality of impedance elements; and

a plurality of surface wave feeds, wherein a surface wave feed in the plurality of surface wave feeds is configured to couple a surface wave channel in the number of surface wave channels of a radiating element in the plurality of radiating elements to a transmission line configured to carry a radio frequency signal.

2. The apparatus of claim 1, wherein the plurality of radiating elements and the plurality of surface wave feeds form an artificial impedance surface antenna that is configured to be electronically steered in a theta direction and a phi direction.

3. The apparatus of claim 2, wherein the artificial impedance surface antenna operates at a frequency between about 26.5 gigahertz and about 40 gigahertz.

4. The apparatus of claim 2, wherein the artificial impedance surface antenna operates at a frequency of about 30 gigahertz with an aperture efficiency greater than about 25 percent.

5. The apparatus of claim 2, wherein the plurality of switch elements of each surface wave channel of the number of surface wave channels enables creating a surface impedance profile of high surface impedance and low surface impedance for the each surface wave channel.

6. The apparatus of claim 5, wherein the surface impedance profile is a square-wave-type modulation.

7. The apparatus of claim 5, wherein the high surface impedance and the low surface impedance are modulated to enable scanning in the theta direction and in the phi direction.

8. The apparatus of claim 1, wherein each switch element in the plurality of switch elements is a PIN diode that has an inductance state and a capacitance state.

9. The apparatus of claim 1, wherein each switch element in the plurality of switch elements is a Schottky diode that has only two states.

10. The apparatus of claim 1, wherein each switch element in the plurality of switch elements is a semiconductor switch that has only two states.

11. The apparatus of claim 1, wherein each switch element in the plurality of switch elements is a microelectromechanical systems switch diode that has only two states.

12. The apparatus of claim 1, wherein each switch element in the plurality of switch elements is a phase-change material switch that has only two states.

13. The apparatus of claim 1, wherein each switch element in the plurality of switch elements is a high frequency diode that has only two states.

14. The apparatus of claim 1, wherein an impedance element in the plurality of impedance elements is selected from one of a metallic strip, a patch of conductive paint, a metallic mesh material, a metallic film, a deposit of a metallic substrate, a resonant structure, a split-ring resonator, and an electrically-coupled resonator, a structure comprised of one or more metamaterials.

15. The apparatus of claim 1, wherein an impedance element in the plurality of impedance elements has a pattern formed by a series of a same shape.

16. The apparatus of claim 15, wherein the same shape is selected from one of a diamond-type shape and a hexagonal-type shape.

17. An artificial impedance surface antenna comprising:

a plurality of radiating elements, wherein each of the plurality of radiating elements comprises a number of surface wave channels in which each of the number of surface wave channels is configured to constrain a path of a surface wave and comprises;

a plurality of impedance elements located on a surface of a dielectric substrate; and

a plurality of switch elements located on the surface of the dielectric substrate in which each of the plurality of switch elements has a first state and a second state; and

a plurality of surface wave feeds configured to couple the number of surface wave channels of each of the plurality of radiating elements to a number of transmission lines.

18. A method for electronically steering an antenna system, the method comprising:

propagating a surface wave along each of a number of surface wave channels formed in each of a plurality of radiating elements to form a radiation pattern;

coupling each surface wave channel in the number of surface wave channels formed in each radiating element in the plurality of radiating elements to a transmission line configured to carry a radio frequency signal using a surface wave feed in a plurality of surface wave feeds associated with the plurality of radiating elements; and

electronically steering a main lobe of the radiation pattern by controlling voltages applied to a plurality of switch elements connecting a plurality of impedance elements in each of the number of surface wave channels.

19. The method of claim 18, wherein electronically steering the main lobe comprises:

applying a first level of voltage or a second level of voltage to each of the plurality of switch elements to create a surface impedance profile for each surface wave channel of the number of surface wave channels.

20. The method of claim 18, wherein electronically steering the main lobe comprises:

applying a first level of voltage or a second level of voltage to each of the plurality of switch elements to modulate between high surface impedance and low surface impedance.