Highly agile wideband cavity impedance matching

• US 8,681,068 B1
• Filed: 09/14/2010
• Issued: 03/25/2014
• Est. Priority Date: 09/15/2009
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Williams, Brett A., Schuder, Kurt S., Zamarron, J. Michael
• Primary Examiner(s): Jackson, Jr., Jerome
• Assistant Examiner(s): Lindgren Baltzell, Andrea
• Application Number:
  US12/881,946
• Time in Patent Office: 1,288 Days
• Field of Search: 343/705, 343/789, 343/841, 343/895, 342/54, 342/62
• US Class Current: 343/841
• CPC Class Codes: H01Q 1/52 Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure absorbing means H01Q17/00
• CPC Class Codes: H01Q 9/27 Spiral antennas

Abstract

A technique for suppressing backwaves employs a photonic approach. In one aspect, the technique includes an apparatus, including: a radiating element; and a microwave-photonic device for suppressing backwaves from the radiating element. In a second aspect, the technique includes a method for removing unwanted radiation from a radiating device, comprising: receiving unwanted radiation from the radiating device; communicating the received radiation to an electro-optically active material; communicating laser light to the electro-optically active material; communicating electromagnetic products of interactions between the radiation and the laser light to a photodiode; and communicating photodiode outputs to a termination.

Claims

1. A microwave-photonic device for removing a backwave from a radiating device spiral antenna, comprising:

a tuner configured to tune the microwave-photonic device to receive backwave radio frequency (RF) energy at a selected RF band from the radiating device spiral antenna;

an electro-optically active material;

means for communicating laser light to the electro-optically active material;

a photodiode;

means for communicating electromagnetic products of interactions between radiation and laser light to the photodiode; and

means for communicating outputs of the photodiode to a ground to eliminate the backwave RF energy.

2. The microwave-photonic device of claim 1, wherein the electromagnetic products of interactions between radiation and laser light enter a series of electro-optically active materials subsequent to the first.

3. The microwave-photonic device of claim 1, further comprising a horseshoe conductor on a surface of the electro-optically active material, the horseshoe conductor coupled to a wire/microstrip/stripline.

4. The microwave-photonic device of claim 1, wherein the means for communicating laser light to the electro-optically active material comprises a prism.

5. The microwave-photonic device of claim 1, wherein the means for communicating the electromagnetic products of interactions between radiation and laser light to the photodiode comprises freespace optics that guide light out of the electro-optically active material to the photodiode.

6. The microwave-photonic device of claim 1, wherein the means for communicating the outputs of the photodiode to the ground comprises copper wire, a micro strip, or a stripline.

7. A method for removing a backwave from a radiating device spiral antenna, comprising:

tuning an electro-optically active material to receive backwave radio frequency (RF) energy at a selected RF band;

receiving, by the electro-optically active material, the backwave RF energy at the selected band from the radiating device spiral antenna;

communicating laser light to the electro-optically active material;

communicating electromagnetic products of interactions between the radiation and the laser light to a photodiode; and

communicating outputs of the photodiode to a ground to eliminate the backwave RF energy.

8. A microwave-photonic device, comprising:

an electro-optically active material;

a tuner configured to tune the electro-optically active material to receive backwave radio frequency (RF) energy at a selected RF band from a radiating device spiral antenna;

a conductor capable of communicating the backwave RF energy at the selected RF band to the electro-optically active material;

a prism through which laser light is communicated to the electro-optically active material;

a photodiode;

means for communicating electromagnetic products of interactions between radiation and laser light to the photodiode; and

means for communicating outputs of the photodiode to a ground to eliminate the backwave RF energy.

9. The microwave-photonic device of claim 8, wherein the means for communicating the electromagnetic products of interactions between radiation and laser light to the photodiode comprises freespace optics that guide light out of the electro-optically active material to the photodiode.

10. The microwave-photonic device of claim 8, wherein the means for communicating the outputs of the photodiode to the ground comprises copper wire, a micro strip, or a stripline.

11. An apparatus, comprising:

a radiating device spiral antenna; and

a microwave-photonic device for suppressing backwave radio frequency (RF) energy at a selected RF band from the radiating device spiral antenna, the microwave-photonic device comprising;

an electro-optically active material;

a tuner configured to tune the electro-optically active material to receive backwave RF energy at a selected RF band from a radiating device the spiral antenna;

a conductor capable of communicating the backwave RF energy at the selected RF band to the electro-optically active material;

a prism through which laser light is communicated to the electro-optically active material;

a photodiode;

a light guide configured to communicate electromagnetic products of interactions between radiation and laser light to the photodiode; and

a conductor configured to communicate outputs of the photodiode to a ground to eliminate the backwave RF energy.

12. The apparatus of claim 11, wherein the radiating device spiral antenna comprises a plurality of spirals.

13. An antenna, comprising:

a spiral radiating device element; and

a microwave-photonic device for suppressing backwave radio frequency (RF) energy at a selected RF band from the spiral radiating device element, the microwave-photonic device comprising;

an electro-optically active material;

a tuner configured to tune the electro-optically active material to receive backwave RF energy at a selected RF band from the spiral radiating device element;

a conductor capable of communicating the backwave RF energy at the selected RF band to the electro-optically active material;

a prism through which laser light is communicated to the electro-optically active material;

a photodiode;

a light guide configured to communicate electromagnetic products of interactions between radiation and laser light to the photodiode; and

a conductor configured to communicate outputs of the photodiode to a ground to eliminate the backwave RF energy.

14. The antenna of claim 13, wherein the spiral radiating device element comprises a plurality of spirals.

15. A missile, including:

a spiral antenna mounted on the missile;

a backwave suppression mechanism for suppressing backwave radio frequency (RF) energy at a selected RF band from the spiral antenna, comprising;

an electro-optically active material;

a tuner configured to tune the electro-optically active material to receive the backwave RF energy at the selected RF band from the spiral antenna;

a conductor capable of communicating the backwave RF energy at the selected RF band to the electro-optically active material;

a prism through which laser light is communicated to the electro-optically active material;

a photodiode;

a light guide configured to communicate electromagnetic products of interactions between radiation and laser light to the photodiode; and

a conductor configured to communicate outputs of the photodiode to a ground to eliminate the backwave RF energy; and

a guidance and navigation control system for guiding the missile responsive to information obtained through the spiral antenna.