Phased-array radio frequency receiver and methods of operation

Patent metadata

Field	Value
Publication number	US-11205843-B2
Application number	US-201916401072-A
Country	US
Kind code	B2
Filing date	May 1, 2019
Priority date	May 1, 2018
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

An RF receiver may include antenna elements to receive RF signals, and electro-optic modulators to generate corresponding upconverted optical signals by mixing an RF signal with an optical carrier beam. The RF receiver may include a transmission array having a first bundle of optical waveguides that receive and transmit upconverted optical signals from their ends. The ends may be arranged in a first pattern. The RF receiver may include an interference space to receive the upconverted optical signals to form a composite beam, and an array of single mode optical fibers that have lenses positioned in a detection plane to receive a portion of the composite beam. The first pattern of the ends generates an RF emitter interference pattern at the detection plane, and the single mode optical fiber lenses have a geometric arrangement that corresponds to the first RF emitter interference pattern.

First claim

What is claimed is:

1. An RF receiver, comprising:
a plurality of antenna elements configured to receive RF signals;
a plurality of electro-optic modulators, each electro-optic modulator being in communication with a corresponding one of the plurality of antenna elements to receive a corresponding electrical RF signal, the plurality of electro-optic modulators being configured to generate a corresponding upconverted optical signal by mixing the corresponding electrical signal with an optical carrier beam;
a transmission array comprising a first bundle of optical waveguides, each optical waveguide having an end and being in communication with a corresponding one of the plurality of electro-optic modulators to receive and transmit a respective upconverted optical signal, the ends of the optical waveguides of the first bundle being arranged in a first pattern;
an interference space to receive the plurality of upconverted optical signals transmitted by the first bundle of optical waveguides to form a composite beam; and
a sensor array comprising a plurality of sensors arranged in a detection plane, and being in optical communication with the interference space to receive the composite beam, each of the sensors of the array being positioned to receive a respective portion of the composite beam impinged thereon,
wherein the first pattern of the ends of the optical waveguides of the first bundle is configured to generate a first RF emitter interference pattern at the detection plane in response to a first RF signal received by the plurality of antenna elements from a first RF emitter, and
wherein the sensor array comprises:
an array of optical lenses arranged in the detection plane to receive the respective portions of the composite beam impinged thereon, the array of optical lenses arranged in a second pattern that corresponds to the first RF emitter interference pattern;
a second bundle of optical waveguides, each optical waveguide of the second bundle being in communication with a corresponding one of the optical lenses; and
a plurality of photodetectors configured to detect a respective portion of the composite beam,

wherein each optical lens of the array of optical lenses is in optical communication with a corresponding waveguide and each waveguide is in optical communication with a corresponding photodetector, and
wherein each optical waveguide of the second bundle of optical waveguides is a single mode optical waveguide.

2. The RF receiver of claim 1 , further comprising an optical source providing a reference optical beam,
wherein the optical carrier beam has a first frequency and the reference optical beam has a second frequency, the first frequency and second frequency differ by a set amount.

3. The RF receiver of claim 2 , further comprising an input to control the set amount.

4. The RF receiver of claim 1 , further comprising a lens located in the interference space and positioned in the path of the composite beam,
wherein the detection plane is an image plane of the lens.

5. The RF receiver of claim 1 , comprising a filter that is positioned within the interference space, the filter being configured to isolate a sideband from at least one upconverted optical signal.

6. The RF receiver of claim 5 , comprising:
a beam splitter that is positioned within the interference space, wherein:
the composite beam corresponds to at least a first received RF frequency and a second received RF frequency,
the beam splitter is configured to divide the composite beam into a plurality of separate beams, and
the sensor array is configured to receive a respective portion of the plurality of separate beams impinged thereon.

7. The RF receiver of claim 2 , wherein:
the transmission array further comprises a central optical waveguide having an end that is centrally located with respect to the ends of the optical waveguides of the first bundle, and
wherein the central optical waveguide is in optical communication with the optical source to receive the reference optical beam and to transmit the reference optical beam into the interference space.

8. The RF receiver of claim 1 , further comprising an optical splitter configured to split a reference beam into a plurality of reference beam portions, each of the plurality of reference beam portions being provided to a respective beam combiner configured to combine the respective reference beam portion with a respective portion of the composite beam.

9. The RF receiver of claim 1 , wherein:
the first pattern of the ends of the optical waveguides of the first bundle is configured to generate the first RF emitter interference pattern at the detection plane in response to a first RF signal received by the plurality of antenna elements and a second RF emitter interference pattern at the detection plane in response to a second RF signal received by the plurality of antenna elements.

10. The RF receiver of claim 1 , wherein the plurality of antenna elements are spatially arranged in a third pattern that corresponds to the first pattern.

11. The RF receiver of claim 1 , wherein the first RF emitter interference pattern at the detection plane comprises variation in optical energy of the composite beam forming a plurality of local maximums of optical energy and local minimums of optical energy, the local maximums being spatially separated from one another along the detection plane and the local minimums being spatially separated from one another along the detection plane.

12. The RF receiver of claim 11 , wherein the spatial separation of the plurality of local maximums of optical energy and the spatial separation of the plurality of local minimums of optical energy is a function of the first pattern.

13. The RF receiver of claim 11 , wherein at least one of the sensors of the sensor array is positioned at a local minimum of the first RF emitter interference pattern.

14. The RF receiver of claim 11 , wherein all but one of the sensors of the sensor array are spaced apart from one another such that they have a spacing corresponding to the spacing of the plurality of local minimums of optical energy of the first RF emitter interference pattern.

15. The RF receiver of claim 1 ,
wherein the first RF emitter interference pattern at the detection plane comprises variation in optical energy of the composite beam forming a plurality of local maximums of optical energy and local minimums of optical energy, the local maximums being spatially separated from one another along the detection plane and the local minimums being spatially separated from one another along the detection plane, and
wherein the first pattern of the ends of the optical waveguides of the first bundle is configured to generate the first RF emitter interference pattern at the detection plane in response to a first RF signal received by the plurality of antenna elements and a second RF emitter interference pattern at the detection plane in response to a second RF signal received by the plurality of antenna elements.

16. The RF receiver of claim 15 , further comprising a second sensor array that includes a plurality of second sensors arranged in the detection plane and being positioned to receive a respective portion of the composite beam impinged thereon.

17. The RF receiver of claim 16 , wherein at least one of the second sensors of the second sensor array is positioned at a local minimum of the second RF emitter interference pattern.

18. The RF receiver of claim 16 , wherein at least some of the second sensors of the second sensor array are positioned apar

Assignees

• Phase Sensitive Innovations Inc

Inventors

• Schneider Garrett
• Schuetz Christopher
• Murakowski Janusz
• Dillon Tom
• Shi Shouyuan
• Prather Dennis

Classifications

• G01S7/4816

  of receivers alone · CPC title

• G01S7/4818

  using optical fibres · CPC title

• H01Q3/2611 Primary

  Means for null steering; Adaptive interference nulling · CPC title

• G01S7/4912

  Receivers · CPC title

• G02F2/004 Primary

  Transferring the modulation of modulated light, i.e. transferring the information from one optical carrier of a first wavelength to a second optical carrier of a second wavelength, e.g. all-optical wavelength converter · CPC title