Phased-array radio frequency receiver

Patent metadata

Field	Value
Publication number	US-12021565-B2
Application number	US-202218070802-A
Country	US
Kind code	B2
Filing date	Nov 29, 2022
Priority date	Jul 3, 2014
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A method of RF signal processing comprises receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern. The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals that each have at least one sideband. The modulated signals are directed along a corresponding plurality of optical channels with outputs arranged in a second pattern corresponding to the first pattern. A composite optical signal is formed using light emanating from the outputs of the plurality of optical channels. Non-spatial information contained in at least one of the received RF signals is extracted from the composite signal.

First claim

What is claimed is:

1. A method of RF signal processing comprising:
receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern;
modulating the received RF signals from each of the plurality of antenna elements onto an optical carrier to generate a plurality of modulated signals, each modulated signal having at least one sideband;
directing each of the plurality of modulated signals along a corresponding one of a plurality of optical channels, each of the plurality of optical channels having an output;
forming a composite optical signal using light emanating from the outputs of the plurality of optical channels;
with a first detector, receiving at least a portion of the composite optical signal to identify a first encoded signal within the composite optical signal; and
with a second detector, receiving at least a portion of the composite optical signal to extract the first encoded signal,
wherein the first detector comprises an array of first photodetectors and the second detector comprises a second photodetector that is relatively fast as compared to the first photodetectors.

2. The method of claim 1 , further comprising forming an image based on the received RF signals.

3. The method of claim 1 , wherein the outputs of the plurality of optical channels emanate light to an interference space.

4. The method of claim 1 , further comprising isolating a sideband of each of the modulated signals.

5. The method of claim 1 , wherein the extracting step comprises identifying an angle of arrival of a first incoming RF signal from a first RF source in real time.

6. The method of claim 1 , wherein the extracting step comprises steering at least a portion of the composite optical signal onto the second detector based on information obtained by the first detector, and heterodyning it with an optical reference signal.

7. The method of claim 1 , wherein identifying the first encoded signal comprises identifying, with the first detector, a signal position within an interference pattern of the composite optical signal.

8. The method of claim 1 , further comprising, in response to the first detector, steering the composite optical signal to direct the composite optical signal onto the second detector.

9. The method of claim 1 , wherein the first encoded signal is a frequency-division multiplexed signal comprising multiple carrier signals that are orthogonal to each other.

10. An RF receiver comprising:
a phased-array antenna including a plurality of antenna elements arranged in a first pattern configured to receive RF signals from at least one RF source;
a plurality of electro-optic modulators corresponding to the plurality of antenna elements, each modulator configured to modulate an optical carrier with a received RF signal to generate a plurality of modulated optical signals;
a plurality of optical channels configured to carry the plurality of modulated optical signals, each of the plurality of optical channels having an output to emanate the corresponding modulated optical signal out of the corresponding optical channel;
a composite signal channel, adjacent to the plurality of outputs of the plurality of optical channels, configured to receive the plurality of modulated optical signals to form a composite optical signal;
a first detector configured to receive at least a portion of the composite optical signal to identify a first encoded signal within the composite optical signal; and
a second detector configured to receive at least a portion of the composite optical signal and to extract the first encoded signal from the composite optical signal,
wherein the first detector comprises an array of first photodetectors and the second detector comprises a second photodetector that is relatively fast as compared to the first photodetectors.

11. The RF receiver of claim 10 , further comprising a filter configured to isolate a sideband from at least one modulated optical signal.

12. The RF receiver of claim 11 , wherein the filter is located within the composite signal channel.

13. The RF receiver of claim 10 , wherein the composite signal channel comprises an interference space adjacent the outputs of the plurality of optical channels.

14. The RF receiver of claim 10 , wherein the at least one RF source comprises a first RF source and the first detector is configured to identify a first signal position from the composite optical signal that is responsive to the position of the first RF source.

15. The RF receiver of claim 14 , wherein the second detector is further configured to extract the first encoded signal within the composite optical signal based on the identified first signal position.

16. The RF receiver of claim 14 , wherein the first detector is configured to receive the composite optical signal to identify an angle of arrival of an RF signal of the first RF source in real time.

17. The RF receiver of claim 10 , further comprising:
means for steering the composite optical signal, the means for steering the composite optical signal being responsive to the first detector to direct the composite optical signal onto the second detector.

18. The RF receiver of claim 10 ,
wherein the first detector is configured to receive the composite optical signal to identify spatial positions within the composite optical signal of a plurality of spatially separate information bearing signals including the first encoded signal, each identified spatial position being a function of a spatial position of a corresponding RF source.

19. The RF receiver of claim 18 , wherein:
wherein the second photodetector is one of a plurality of second photodetectors of the second detector, each configured to receive a corresponding one of the spatially separate information bearing signals in response to their spatial positions as identified by the first detector.

20. The RF receiver of claim 19 , wherein each second photodetector receives power corresponding to a different RF source.

21. The RF receiver of claim 10 , wherein the first photodetectors are unable to detect information present in the first encoded signal with the same performance as the second photodetector.

22. The RF receiver of claim 10 , wherein the first encoded signal is a frequency-division multiplexed signal comprising multiple carrier signals that are orthogonal to each other.

23. The RF receiver of claim 10 , further comprising a demodulator configured to demodulate the first encoded signal to extract digital data.

24. The RF receiver of claim 10 , wherein the first encoded signal comprises multiple channels of data.

25. The RF receiver of claim 10 ,
wherein the phased-array antenna is configured to simultaneously receive the first encoded signal and a second encoded signal, and
wherein the RF receiver is configured to simultaneously extract the first encoded signal and the second encoded signal from the composite optical signal.

26. The RF receiver of claim 10 , wherein a first spatial position of the first encoded signal within an image plane of the composite optical signal is spaced apart from a second spatial position of a second encoded signal within the image plane of the composite optical signal.

27. The RF receiver of claim 10 , wherein the outputs of the plurality of optical channels are arranged in a second pattern that is related to the first pattern.

Assignees

• Phase Sensitive Innovations Inc

Inventors

• Schuetz Chris
• Murakowski Janusz
• Schneider Garrett
• Shi Shouyuan
• Prather Dennis

Classifications

• H04B10/64

  Heterodyne {, i.e. coherent receivers where, after the opto-electronic conversion, an electrical signal at an intermediate frequency [IF] is obtained} · CPC title

• H04B10/11

  Arrangements specific to free-space transmission, i.e. transmission through air or vacuum · CPC title

• H04B1/16

  Circuits · CPC title

• H04B10/25759 Primary

  Details of the reception of RF signal or the optical conversion before the optical fibre · CPC title

• H04B2210/006

  Devices for generating or processing an RF signal by optical means · CPC title