Phased-array radio frequency receiver

Patent metadata

Field	Value
Publication number	US-11012159-B2
Application number	US-202016736237-A
Country	US
Kind code	B2
Filing date	Jan 7, 2020
Priority date	Jul 3, 2014
Publication date	May 18, 2021
Grant date	May 18, 2021

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; and
extracting, from the composite optical signal, a first encoded signal contained in at least one of the received RF signals.

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 directing the composite signal onto a cueing detector to identify a spatial position of the first encoded signal.

6. The method of claim 1 , wherein the extracting step comprises directing at least a portion of the composite signal onto a signal detector and heterodyning it with an optical reference signal.

7. The method of claim 1 , wherein the extracting step comprises identifying at least one position of an incoming RF signal.

8. The method of claim 7 , wherein identifying at least one position comprises identifying a signal position within an interference pattern.

9. The method of claim 1 , further comprising compensating for a phase shift in at least one RF modulated optical signal.

10. The method of claim 9 , wherein compensating for a phase shift comprises adjusting an electro-optic modulator.

11. 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.

12. The method of claim 1 , further comprising demodulating the first encoded signal to extract digital data.

13. The method of claim 1 , wherein the first encoded signal comprises multiple channels of data.

14. The method of claim 1 ,
wherein receiving comprises simultaneously receiving the first encoded signal and a second encoded signal by the plurality of antenna elements, and
wherein the extracting step comprises extracting the second encoded signal from the composite optical signal.

15. The method of claim 1 , wherein the extracting step comprises identifying a first spatial position of the first encoded signal within an image plane of the composite optical signal and identifying a second spatial position of a second encoded signal within the image plane of the composite optical signal, the second spatial position being spaced apart from the first spatial position.

16. The method of claim 15 , further comprising directing the first encoded signal onto a first signal detector with a first spatial light modulator in response to identifying the first spatial position and directing the second encoded signal onto a second signal detector with a second spatial light modulator in response to identifying the second spatial position.

17. The method of claim 1 , wherein the outputs of the plurality of optical channels are arranged in a second pattern that is related to the first pattern.

18. The method of claim 17 wherein the second pattern corresponds to the first pattern.

19. 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 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; and
a first detector configured to receive at least a portion of the composite optical signal and to extract a first encoded signal from the composite optical signal.

20. The RF receiver of claim 19 , further comprising a filter configured to isolate a sideband from at least one modulated optical signal.

21. The RF receiver of claim 20 , wherein the filter is located within the composite signal channel.

22. The RF receiver of claim 19 , wherein the composite signal channel comprises an interference space adjacent the outputs of the plurality of optical channels.

23. The RF receiver of claim 19 , further comprising a second detector configured to identify a first signal position of the first encoded signal within the composite optical signal.

24. The RF receiver of claim 23 , wherein the at least one source comprises a first RF source and the first signal position is responsive to the position of the first RF source.

25. The RF receiver of claim 23 , wherein the first detector is further configured to extract the first encoded signal within the composite optical signal based on the identified first signal position.

26. The RF receiver of claim 19 , further comprising a phase compensation detector configured to compensate for phase shifts in the modulated optical signals.

27. The RF receiver of claim 23 , wherein the second 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.

28. The RF receiver of claim 19 , further comprising:
a second detector configured to receive at least a portion of the composite optical signal and to extract a second encoded signal from the composite optical signal.

29. The RF receiver of claim 19 , wherein the first encoded signal is a frequency-division multiplexed signal comprising multiple carrier signals that are orthogonal to each other.

30. The RF receiver of claim 19 , further comprising a demodulator configured to demodulate the first encoded signal to extract digital data.

31. The RF receiver of claim 19 , wherein the first encoded signal comprises multiple channels of data.

32. The RF receiver of claim 19 ,
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.

33. The RF receiver of claim 19 , wherein a first spatial position of the first encoded signal within

Assignees

• Phase Sensitive Innovations Inc

Inventors

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

Classifications

• 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

• H01Q3/2676 Primary

  Optically controlled phased array · CPC title

• H04B10/5165 Primary

  Carrier suppressed; Single sideband; Double sideband or vestigial · CPC title

• H04B1/16

  Circuits · CPC title