Photonically controlled, phased array antenna

• US 6,208,293 B1
• Filed: 11/18/1998
• Issued: 03/27/2001
• Est. Priority Date: 11/21/1997
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Edward, Brian J., Cleaveland, Bryan L., Adams, Stephen B.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): MULL, FRED H
• Application Number:
  US09/193,888
• Time in Patent Office: 860 Days
• Field of Search: 342/368, 342/371, 342/372, 342/374, 342/54, 343/721, 343/772
• US Class Current: 342/368
• CPC Class Codes: G02B 6/4295 coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/2676 Optically controlled phased array

Abstract

A photonically controlled antenna element made of a material such as silicon is disclosed wherein one or more of such antenna elements are mounted in an array on a light waveguide made of glass or sapphire. Light is injected into the light waveguide and reflects therein until it is absorbed by the antenna elements due to the higher refractive index of silicon which makes the reflection break down, and thus allows the laser beam to leak out of the waveguide into the silicon antenna elements. When the photonically controlled antenna elements are illuminated they are switched to a conductive state and can transmit and receive electromagnetic signals. When no light is injected into the light waveguide the photonically controlled antenna elements are not illuminated and are in a non-conductive state wherein they cannot receive or transmit electromagnetic signals. A number of these light waveguides with their antenna arrays thereon may be stacked together to form a single antenna system. When the antenna elements on each light waveguide are designed to operate at different frequencies an extremely broadband antenna system is the result. By providing appropriate time or phase delay to the signals going to each antenna array on a light waveguide a phased array antenna is the result with the ability to electronically steer the radiated electromagnetic signal. Different portions of the broadband antenna system may be operating at the same time, with some parts transmitting and other parts receiving electromagnetic energy.

Claims

1. A photonically controlled antenna comprising:

a light waveguide;

at least one photonically controlled antenna element bonded to the surface of said light waveguide;

means for applying light energy to said light waveguide, said light energy being reflected in said light waveguide until being absorbed by said at least one photonically controlled antenna element through the surface of said light waveguide; and

wherein said at least one photonically controlled antenna element is switched to a conductive state wherein it can transmit and receive electromagnetic energy when said light energy is applied to said light waveguide by said applying means, and said at least one photonically controlled antenna element is switched to a non-conductive state wherein it cannot transmit and receive electromagnetic energy when said light energy is removed from said light waveguide by said applying means.

2. The invention in accordance with claim 1 wherein said light waveguide comprises a piece of light conductive material such as glass or sapphire on one surface of which said at least one photonically controlled antenna is bonded.

3. The invention in accordance with claim 2 wherein said light waveguide further comprises reflection means placed on other surfaces of said light waveguide to assist in reflecting light within said light waveguide by said light energy applying means until said light is absorbed by said photonically controlled antenna element through the surface of said light waveguide.

4. The invention in accordance with claim 3 further comprising means for facilitating the transfer of light energy reflecting inside said light waveguide to said photonically controlled antenna elements so that said photonically controlled antenna elements can change to its conducting state when illuminated by a lesser amount of light energy in said light waveguide.

5. The invention in accordance with claim 4 further comprising a plurality of said light waveguides all stacked together next to each other to create an antenna array, and different ones of said light waveguides are designed to operate over different frequency ranges, said plurality of light waveguides thereby making up an extremely broadband antenna.

6. The invention in accordance with claim 5 wherein each of said light waveguides has a plurality of photonically controlled antenna elements bonded to its surface to create an array of antenna elements on each of said light waveguides.

7. The invention in accordance with claim 6 wherein a signal is applied to said photonically controlled antenna elements on each of said light waveguides to be transmitted, and the portion of said last mentioned signal applied to ones of said last mentioned photonically controlled antenna elements are delayed in time or phase so that they cooperate as a phased array antenna that can electronically steer the direction in which said last mentioned signal is radiated as electromagnetic energy.

8. The invention in accordance with claim 7 wherein ones of said stacked plurality of light waveguides can operating independently of others of said stacked plurality of light waveguides, so some photonically controlled antenna elements can be transmitting signals while other photonically controlled antenna elements are receiving signals, and those antennas that are transmitting signals can be transmitting different signals and in different directions.

9. A photonically controlled antenna, comprising:

a light waveguide which comprises a light conductive material;

and a plurality of photonically controlled antenna elements mounted on said light waveguide, wherein each said photonically controlled antenna element is switchable to a conductive state by application of light energy to said light waveguide so as to be able to transmit and receive electromagnetic energy, and wherein each said photonically controlled antenna element is switchable to a non-conductive state by a discontinuation of said application of light energy to said light waveguide so as to be unable to transmit and receive electromagnetic energy.

10. The invention in accordance with claim 9, further comprising means for applying light energy to said light waveguide, wherein said light energy is reflected in said light waveguide until being absorbed by said plurality of photonically controlled antenna elements through the surface of said light waveguide.

11. The invention in accordance with claim 10, further comprising reflection means placed on surfaces of said light waveguide to assist in reflecting light within said light waveguide provided by said light energy applying means until said light is absorbed by said plurality of photonically controlled antenna elements through the surface of said light waveguide.

12. The invention in accordance with claim 10, further comprising means for facilitating the transfer of light energy reflecting inside said light waveguide to said plurality of photonically controlled antenna elements so that said plurality of photonically controlled antenna elements can change to their conducting state when illuminated by a lesser amount of light energy in said light waveguide of photonically.

13. The invention in accordance with claim 9, wherein each of said plurality controlled antenna elements comprises a semiconductor material.

14. The invention in accordance with claim 9 wherein a signal is applied to said photonically controlled antenna elements on said light waveguide to be transmitted, and the portion of said last mentioned signal applied to ones of said last mentioned photonically controlled antenna elements are delayed in time or phase so that they cooperate as a phased array antenna that can electronically steer the direction in which said last mentioned signal is radiated as electromagnetic energy.

15. The invention in accordance with claim 9, further comprising a plurality of said light waveguides stacked together next to each other in spaced relation and each having a plurality of said photonically controlled antenna elements mounted thereon, wherein said photonically controlled antenna elements on different ones of said light waveguides are designed to operate over different frequency ranges, said plurality of light waveguides with said plurality of photonically controlled elements mounted thereon thereby making up a broadband antenna.

16. The invention in accordance with claim 15, wherein ones of said stacked plurality of light waveguides can operate independently of others of said stacked plurality of light waveguides, so some of said plurality of photonically controlled antenna elements can be transmitting signals while others of said plurality of photonically controlled antenna elements are receiving signals, and those of said plurality of photonically controlled antenna elements that are transmitting signals can be transmitting different signals and in different directions.

18. The invention in accordance with claim 9, wherein said light waveguide provides a common mount for said plurality of photonically controlled antenna elements, wherein said light waveguide is formed from a material selected from the group consisting of glass and sapphire, and wherein each of said plurality of photonically controlled antenna elements is formed from a semiconductor material.

19. The invention in accordance with claim 9, wherein said light waveguide comprises a first surface which extends between first and second edge surfaces, wherein said plurality of photonically controlled antenna elements are mounted on said first surface of said light waveguide, wherein said antenna further comprises a light source that is operatively interconnected with said first edge surface of said light waveguide, and wherein at least one of said first and second edge surfaces comprise a reflective material.

20. The invention in accordance with claim 19, wherein each of said first and second edge surfaces comprise a reflective material.

17. A method for enabling and disabling a photonically controlled antenna element, said method comprising the steps of:

placing the photonically controlled antenna element on a light waveguide;

selectively injecting light energy into the light waveguide, the light energy reflecting inside the light waveguide until it is absorbed by the photonically controlled antenna element thereon, wherein the photonically controlled antenna element is switched to a conductive state wherein it can transmit and receive electromagnetic energy when the light energy is applied to the light waveguide, and wherein the photonically controlled antenna element is switched to a non-conductive state wherein it cannot transmit and receive electromagnetic energy when the light energy is removed from the light waveguide.