Apparatus and method supporting covert communications using terahertz imaging camera

• US 9,413,469 B2
• Filed: 12/11/2014
• Issued: 08/09/2016
• Est. Priority Date: 07/02/2012
• Status: Active Grant

• Current Assignee: Dayton D. Eden
• Original Assignee: Dayton D. Eden
• Inventors: Eden, Dayton D.
• Primary Examiner(s): Czekaj, Dave
• Assistant Examiner(s): HAQUE, MD NAZMUL
• Application Number:
  US14/567,890
• Publication Number:
  US 20150092063A1
• Time in Patent Office: 607 Days
• US Class Current: 1/1
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/0803 Arrangements for time-dependent attenuation of radiation signals
• CPC Class Codes: G01J 5/0837 Microantennas, e.g. bow-tie
• CPC Class Codes: G01J 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: G01J 5/20 using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
• CPC Class Codes: G01J 5/22 Electrical features thereof
• CPC Class Codes: G01V 3/10 using induction coils
• CPC Class Codes: G01V 8/005 operating with millimetre waves, e.g. measuring the black losey radiation
• CPC Class Codes: H04B 10/67 Optical arrangements in the receiver
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

An apparatus includes a link receiver having a detector array configured to receive radiation from a remote communication device, where the detector array includes multiple detectors. Each detector includes a horn receiver configured to capture the radiation using an antenna positioned in or proximate to a throat of the horn receiver, where the antenna is coupled to an antenna load. Each detector also includes a bolometer electrically isolated from the antenna load and in thermal contact with the antenna load. The link receiver could include a terahertz camera. The detector array can be located at a focal plane of an optical system configured to receive the radiation through a specified far-field solid angle. The apparatus could also include a link transmitter configured to generate and transmit second radiation to the remote communication device and/or a communication transmitter/receiver configured to communicate with the remote communication device.

Claims

1. An apparatus comprising:

a link receiver comprising a detector array configured to receive radiation from a remote communication device, the detector array comprising multiple detectors, each detector comprising;

a horn receiver configured to capture the radiation using an antenna positioned in or proximate to a throat of the horn receiver, the antenna coupled to an antenna load; and

a bolometer electrically isolated from the antenna load and in thermal contact with the antenna load.

2. The apparatus of claim 1, wherein the link receiver comprises a terahertz camera.

3. The apparatus of claim 1, wherein the detector array is located at a focal plane of an optical system configured to receive the radiation through a specified far-field solid angle.

4. The apparatus of claim 1, wherein the link receiver is configured to:

identify one or more of the detectors in the detector array that receive the radiation from the remote communication device; and

determine an angular origin of the radiation relative to a central axis of the link receiver.

5. The apparatus of claim 1, further comprising:

a link transmitter configured to generate and transmit second radiation to the remote communication device.

6. The apparatus of claim 1, further comprising:

a communication transmitter/receiver configured to communicate with the remote communication device.

7. The apparatus of claim 6, wherein the communication transmitter/receiver is bore-sighted with the link receiver.

8. The apparatus of claim 1, further comprising:

a metal plate comprising holes and forming a band pass filter, the band pass filter covering an aperture of the link receiver.

24. The apparatus of claim 1, wherein each detector further comprises:

antenna posts having first ends connected to the antenna and extending through irises in a conducting ground plane; and

conductive traces connected to second ends of the antenna posts and electrically coupled to the antenna load;

wherein the antenna and the conductive traces are located on opposing sides of the conducting ground plane.

25. The apparatus of claim 1, wherein the detector array is configured to receive the radiation at a frequency of about 90 GHz to about 300 GHz.

9. A system comprising:

a first communication device comprising;

a link receiver comprising a detector array configured to receive first radiation from a second communication device, the detector array comprising multiple detectors, each detector comprising;

a horn receiver configured to capture the first radiation using an antenna positioned in or proximate to a throat of the horn receiver, the antenna coupled to an antenna load; and

a bolometer electrically isolated from the antenna load and in thermal contact with the antenna load;

a link transmitter configured to transmit second radiation to the second communication device; and

a communication transmitter/receiver configured to communicate with the second communication device.

10. The system of claim 9, wherein:

the link transmitter is bore-sighted with the link receiver; and

the communication transmitter/receiver is bore-sighted with the link receiver.

11. The system of claim 9, wherein the link transmitter and the link receiver are integrated.

12. The system of claim 9, wherein the link transmitter and the link receiver are located next to the communication transmitter/receiver.

13. The system of claim 9, further comprising:

the second communication device comprising;

a second link receiver;

a second link transmitter; and

a second communication transmitter/receiver;

wherein the communication devices are configured to use the link receivers and the link transmitters to identify angular coordinates of one another; and

wherein the communication devices are configured to use the communication transmitters/receivers to exchange information.

14. The system of claim 13, wherein the communication devices are configured to use link pulses to search for one another at a carrier frequency above about 90 GHz.

15. The system of claim 9, wherein the first communication device is configured to maintain aim towards the second communication device using the link transmitter and the link receiver.

16. The system of claim 13, wherein the second communication device is configured to maintain aim towards the first communication device using the second link transmitter and the second link receiver.

17. The system of claim 13, wherein:

the link receivers of the first and second communication devices comprise modified Cassegrain imaging systems; and

the communication transmitters/receivers of the first and second communication devices comprise Cassegrain optical systems.

18. The system of claim 17, wherein:

each modified Cassegrain imaging system comprises a first primary mirror and a first secondary mirror, the associated detector array located at a focal plane of the modified Cassegrain imaging system; and

each Cassegrain optical system comprises a second primary mirror and a second secondary mirror, the associated communication transmitter/receiver located at a focal point of the Cassegrain optical system.

19. A method comprising:

identifying, at a first communication device, angular coordinates to a second communication device using a link receiver at the first communication device; and

communicating with the second communication device using a communication transmitter/receiver of the first communication device;

wherein the link receiver comprises a detector array configured to receive radiation from the second communication device, the detector array comprising multiple detectors, each detector comprising;

a horn receiver configured to capture the radiation using an antenna positioned in or proximate to a throat of the horn receiver, the antenna coupled to an antenna load; and

a bolometer electrically isolated from the antenna load and in thermal contact with the antenna load.

20. The method of claim 19, further comprising:

identifying, at the second communication device, angular coordinates to the first communication device using a second link receiver at the second communication device; and

communicating with the first communication device using a second communication transmitter/receiver of the second communication device;

wherein the second link receiver comprises a second detector array configured to receive second radiation from the first communication device, the second detector array comprising multiple second detectors, each second detector comprising;

a second horn receiver configured to capture the second radiation using a second antenna positioned in or proximate to a second throat of the second horn receiver, the second antenna coupled to a second antenna load; and

a second bolometer electrically isolated from the second antenna load and in thermal contact with the second antenna load.

21. The method of claim 20, wherein:

the link receivers of the first and second communication devices comprise modified Cassegrain imaging systems;

the communication transmitters/receivers of the first and second communication devices comprise Cassegrain optical systems; and

the method comprises;

engaging in mutual wide band communication between the first and second communication devices using the Cassegrain optical systems; and

engaging in mutual communication between the first and second communication devices over a very narrow beam using the modified Cassegrain imaging systems to maintain pointing accuracy.

22. The method of claim 19, further comprising:

transmitting second radiation to the second communication device using a link transmitter of the first communication device.

23. The method of claim 19, further comprising:

filtering the radiation from the second communication device using a plate comprising holes and forming a band pass filter.