Same-aperture any-frequency simultaneous transmit and receive communication system

• US 10,425,121 B2
• Filed: 02/21/2018
• Issued: 09/24/2019
• Est. Priority Date: 07/30/2012
• Status: Active Grant

• Current Assignee: Photonic Systems Inc. (Photonics Systems Holding GmbH)
• Original Assignee: Photonic Systems Inc. (Photonics Systems Holding GmbH)
• Inventors: Cox, Charles H., Ackerman, Edward I.
• Primary Examiner(s): Tran, Tuan A
• Application Number:
  US15/901,729
• Publication Number:
  US 20180183486A1
• Time in Patent Office: 580 Days
• Field of Search: None
• CPC Class Codes: G01S 7/023 Interference mitigation, e.g. reducing or avoiding non-intentional interference with other HF-transmitters, base station transmitters for mobile communication or other radar systems, e.g. using electro-magnetic interference [EMI] reduction techniques auxiliary means for detecting or identifying radar signals or the like G01S7/021; means for anti-jamming G01S7/36
• CPC Class Codes: G01S 7/034 Duplexers switching devices for waveguides H01P1/10; transmit-receive switching in transceivers H04B1/44
• CPC Class Codes: G01S 7/038 Feedthrough nulling circuits
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 1/48 in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter H04B1/46 takes precedence
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions

Abstract

A same-aperture any-frequency simultaneously transmit and receive (STAR) system includes a signal connector having a first port electrically coupled to an antenna, a second port electrically coupled to a transmit signal path, and a third port electrically coupled to receive signal path. The signal connector passes a transmit signal in the transmit signal path to the antenna and a receive signal in the receive signal path. A signal isolator is positioned in the transmit signal path to remove a residual portion of the receive signal from transmit signal path. An output of the signal isolator provides a portion of the transmit signal with the residual portion of the receive signal removed. A signal differencing device having a first input electrically coupled to the output of the signal isolator and a second input electrically coupled to the third port of the signal connector subtracts a portion of the transmit signal in the receive signal path thereby providing a more accurate receive signal.

Claims

1. A same-aperture any-frequency simultaneously transmit and receive (STAR) system, the system comprising:

a) a signal connector having a first port, a second port electrically coupled to a transmit signal path and a third port electrically coupled to a receive signal path, the signal connector passing a transmit signal in the transmit signal path to the first port and a receive signal in the receive signal path from the first port, wherein the transmit signal and the receive signal occupy a same signal frequency band at a same time;

b) a signal differencing device having a first input electrically coupled to the transmit signal path and a second input electrically coupled to the third port of the signal connector, the signal connector and the signal differencing device being configured to support a transmit signal in the receive signal path with a power that is a same order of magnitude or a greater order of magnitude than a power of the receive signal in the receive signal path, the signal differencing device subtracting a portion of the transmit signal in the receive signal path, thereby providing a more accurate copy of the receive signal at an output; and

c) a signal processor having an input coupled to the output of the signal differencing device and an output coupled to the first input of the signal differencing device, the signal processor executing an algorithm to determine a value of the transmit signal provided to the signal differencing device.

2. The system of claim 1 wherein the signal connector provides a matched impedance for at least one of the first, second and third ports.

3. The system of claim 1 wherein the signal connector provides a higher impedance at the second port than at either the first and the second ports.

4. The system of claim 1 wherein the signal connector comprises a fast switch.

5. The system of claim 1 wherein the signal differencing device is an active differencing device.

6. The system of claim 1 wherein the signal differencing device is a passive differencing device.

7. The system of claim 1 wherein the signal differencing device is a photonic differencing device.

8. The system of claim 1 further comprising a signal isolator positioned in the transmit signal path that removes a residual portion of the receive signal from the transmit signal path, an output of the signal isolator providing the portion of the transmit signal from which the residual portion of the receive signal has been removed.

9. The system of claim 8 wherein the signal isolator is an electronic voltage-source-based isolator.

10. The system of claim 8 wherein the signal isolator is a current-source-based signal isolator.

11. The system of claim 8 wherein the signal isolator is a non-reciprocal RF isolator.

12. The system of claim 8 wherein the signal isolator is an electronic voltage-source-based isolator is a photonic isolator.

13. The system of claim 1 wherein the algorithm executed by the signal processor correlates a copy of the transmit signal with the output of the differencing device and generates a more accurate representation of the receive signal.

14. The system of claim 1 wherein the signal processor generates a signal that when added to the transmit signal path more fully subtracts residual portions of the transmit signal from the resulting difference signal generated by the signal differencing device.

15. The system of claim 1 wherein the signal processor is an analog signal processor.

16. The system of claim 1 wherein the signal processor is a digital signal processor.

17. The system of claim 1 further comprising a feedback system having an input coupled to the output of the signal differencing device and an output coupled to the first input of the signal differencing device, the feedback system generating a signal that when added to the transmit signal path more fully subtracts the transmit signal from the receive signal.

18. The system of claim 17 wherein the feedback system comprises the signal processor and a transmit signal adjuster circuit.

19. The system of claim 17 wherein the feedback system generates at the output a desired complex value of the transmit signal that when added the transmit signal path more fully subtracts the transmit signal from the receive signal path.

20. A method of same-aperture any-frequency simultaneously transmitting and receiving, the method comprising:

a) connecting a receive signal from a first port with a transmit signal from a transmit signal path so that the receive signal is passed to a receive signal path and the transmit signal is passed from the transmit signal path to the first port, wherein the transmit signal and the receive signal occupy a same signal frequency band at a same time;

b) subtracting a portion of the transmit signal in the transmit signal path from the receive signal in the receive signal path wherein the portion of the transmit signal in the receive signal oath comprises a power that is a same order of magnitude or a greater order of magnitude than a power of the receive signal in the receive signal path, thereby removing a residual portion of the transmitted signal from the receive signal path making a more accurate representation of the receive signal; and

c) executing an algorithm with a signal processor to determine a value of the transmit signal provided to the signal differencing device.

21. The method of claim 20 wherein the executing an algorithm with a signal processor to determine the value of the transmit signal provided to the signal differencing device comprises correlating a copy of the portion of the transmit signal in the transmit signal path with the receive signal, wherein the correlated copy of the portion of the transmit signal in the transmit signal path with the subtracted signal generates a more accurate representation of the receive signal.

22. The method of claim 20 wherein the connecting the receive signal from the first port with the transmit signal from the transmit signal path comprises fast switching.

23. The method of claim 20 further comprising isolating a portion of the transmit signal from a residual receive signal component in the transmit signal path.

24. The method of claim 23 wherein the isolating is performed non-reciprocally.

25. The method of claim 23 wherein the isolating is performed using photonic isolation.

26. The method of claim 20 wherein the subtracting the portion of the transmit signal in the transmit signal path from the receive signal in the receive signal path is performed using photonic subtraction.

27. The method of claim 20, wherein the subtracting the portion of the transmit signal in the transmit signal path from the receive signal in the receive signal path is performed using electronic subtraction.

28. A same-aperture any-frequency simultaneously transmit and receive (STAR) system, the system comprising:

a) a signal connector that connects a first port to a second port thereby forming a transmit path passing a transmit signal and that connects the first port to a third port thereby forming a receive path passing a receive signal, wherein the transmit signal and the receive signal occupy a same signal frequency band at a same time;

b) a signal differencing device having a first input electrically coupled to the second port of the signal connector and a second input electrically coupled to the third port of the signal connector, the connector and the signal differencing device being configured to support a transmit signal in the receive signal path with a power that is the same order of magnitude or a greater order of magnitude than a power of the receive signal in the receive signal path; and

c) a signal processor having an first input coupled to the output of the signal differencing device, a second input coupled to the transmit signal path and an output coupled to the first input of the signal differencing device, the signal processor executing an algorithm to determine a value of the transmit signal provided to the signal differencing device,

wherein the value of the transmit signal provided to the signal differencing device reduces a residual transmit signal in the receive signal path.