Phased-array radio frequency receiver

Patent metadata

Field	Value
Publication number	US-9800346-B2
Application number	US-201615370035-A
Country	US
Kind code	B2
Filing date	Dec 6, 2016
Priority date	Jul 3, 2014
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

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:
simultaneously receiving incoming RF signals from at least first and second RF sources at each of a plurality of antenna elements;
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, non-spatial information contained in at least one of the received RF signals, the non-spatial information comprising first digital data provided by the first RF source and second digital data provided by the second RF source.

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 a free space.

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

5. The method claim 1 , wherein the extracting step comprises directing the composite signal onto a cueing detector.

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 claim 1 , further comprising compensating for a phase shift in at least one RF modulated optical signal by adjusting an electro-optic modulator.

10. The method of claim 1 , further comprising demodulating first and second OFDM signals to respectively obtain the first digital data and the second digital data.

11. The method of claim 10 , wherein the first OFDM signal is obtained from the composite optical signal by a first photodiode and the second OFDM signal is obtained from the composite optical signal by a second photodiode.

12. The method of claim 1 , wherein the first digital data is obtained from the composite optical signal by a first photodiode and the second digital data is obtained from the composite optical signal by a second photodiode.

13. An RF receiver comprising:
a phased-array antenna including a plurality of antenna elements to simultaneously receive RF signals from at least first and second RF sources;
a plurality of electro-optic modulators corresponding to the plurality of antenna elements, each modulator configured to modulate an optical carrier with the received RF signal of a corresponding antenna element to generate a corresponding modulated optical signal, the plurality of elector-optic modulators thereby configured 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 generate a composite optical signal; and
a detector configured to receive the composite optical signal and to extract non-spatial information from the RF signals received from the first and second RF sources, the non-spatial information comprising first digital data provided by the first RF source and second digital data provided by the second RF source.

14. The RF receiver of claim 13 , further comprising a filter configured to isolate a sideband from at least one modulated optical signal.

15. The RF receiver of claim 14 , wherein the filter is located within the composite signal channel.

16. The RF receiver of claim 13 , wherein the composite signal channel comprises a free space adjacent the outputs of the plurality of optical channels.

17. The RF receiver of claim 13 , wherein the detector is configured to identify a signal position from the composite optical signal.

18. The RF receiver of claim 17 , wherein the signal position correlates with a spatial position of the at least one source.

19. The RF receiver of claim 17 , wherein the detector is further configured to detect a received RF signal from at least one source based on the identified signal position.

20. The RF receiver of claim 13 , further comprising a phase compensation detector configured to compensate for phase shifts in the modulated optical signals.

21. The RF receiver of claim 13 , wherein the detector comprises a cueing detector configured to use the composite optical signal to identify a signal position that corresponds to a spatial position of an RF source.

22. The RF receiver of claim 13 , further comprising:
a second detector; and
a spatial-light-modulator configured to direct the composite optical signal onto the second detector.

23. The RF receiver of claim 13 , wherein the first detector comprises a first photodetector to detect the first digital data from the composite optical signal and a second photodetector to detect the second digital data.

24. The RF receiver of claim 23 , wherein the first digital data is encoded in a first OFDM signal detected by the first photodetector and the second digital data is encoded in a second OFDM signal detected by the second photodetector.

25. The RF receiver of claim 13 , further comprising a cueuing detector to detect the first and second RF sources from first and second bright spots of the composite optical signal.

26. The RF receiver of claim 13 , wherein the plurality of antenna elements are arranged in a first pattern and the plurality of optical channels are arranged in a second pattern corresponding to the first pattern.

27. An RF receiver comprising:
a phased-array antenna including a plurality of antenna elements to simultaneously receive RF signals from different sources;
a plurality of electro-optic modulators configured to modulate an optical carrier with the received RF signals to generate a plurality of modulated optical signals, each modulator corresponding to one of the plurality of the antenna elements;
a plurality of optical channels configured to carry the plurality of modulated optical signals, the plurality of optical channels having a plurality of outputs;
a composite signal channel adjacent the plurality of outputs of the plurality of optical channels configured to receive the plurality of modulated optical signals, to thereby provide a composite optical signal; and
a first detector configured to receive the composite optical signal to identify a non-spatial attribute of each of the received RF signals from the different sources based on the composite optical signal.

28. The RF receiver of claim 27 , wherein the first detector comprises a first photodetector to detect the first digital data from the composite optical signal and a second photodetector to detect th

Assignees

• Phase Sensitive Innovations Inc

Inventors

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

Classifications

• H04B2210/006

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

• 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