Antenna subsystem with analog beam-steering transmit array and digital beam-forming receive array

• US 10,684,354 B2
• Filed: 12/05/2017
• Issued: 06/16/2020
• Est. Priority Date: 12/05/2016
• Status: Active Grant

• Current Assignee: Echodyne Corp.
• Original Assignee: Echodyne Corp.
• Inventors: Brune, Nicholas K., Chatni, Muhammad Rameez, Driscoll, Tom, Hull, Jonathan R., Hunt, John Desmond, Lambrecht, Christopher L., Landy, Nathan Ingle, Perque, Milton, Renneberg, Charles A., Sikes, Benjamin, Teeslink, Tarron, Tzanidis, Ioannis, Worl, Robert Tilman, Bily, Adam
• Primary Examiner(s): McGue, Frank J
• Application Number:
  US15/832,568
• Publication Number:
  US 20180156891A1
• Time in Patent Office: 924 Days
• Field of Search: 342 81
• CPC Class Codes: G01S 13/4463 using phased arrays
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 13/206 Microstrip transmission line antennas
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 21/005 Slotted waveguides arrays
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/34 by electrical means active lenses or reflecting arrays H01Q3/46

Abstract

In an embodiment, an antenna subsystem includes a sparse receive antenna and an electronically steerable transmit antenna. The sparse receive antenna includes an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength. And the electronically steerable transmit antenna includes an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength. To reduce aliasing, such an antenna subsystem can be operated to filter, spatially, a receive beam pattern generated by the receive antenna with a transmit beam pattern generated by the transmit antenna.

Claims

1. An antenna subsystem, comprising:

a sparse receive antenna including an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength; and

an electronically steerable transmit antenna including an array of transmit elements each configured to radiate a respective signal having the wavelength and each spaced apart from each adjacent one of the transmit elements by a respective second distance that is less than one half of the wavelength.

2. The antenna subsystem of claim 1 wherein the sparse receive antenna includes no fewer than eight, and no more than sixty four, receive elements.

3. The antenna subsystem of claim 1 wherein each first distance is at least five times the wavelength.

4. The antenna subsystem of claim 1 wherein at least one of the first distances is at least ten times the wavelength.

5. The antenna subsystem of claim 1 wherein the electronically steerable transmit antenna includes multiple transmit-antenna sections each including a respective subarray of the transmit elements.

6. The antenna subsystem of claim 1 wherein the electronically steerable transmit antenna includes:

a first transmit-antenna section having a first subarray of the transmit elements; and

a second transmit-antenna section having a second subarray of the transmit elements and offset from the first transmit-antenna section.

7. The antenna subsystem of claim 1 wherein each second distance is no greater than one tenth of the wavelength.

8. The antenna subsystem of claim 1 wherein the electronically steerable transmit antenna includes a metamaterial electronically steerable transmit antenna.

9. The antenna subsystem of claim 1 wherein the array of the electronically steerable transmit antenna is configured as an oversampling array.

10. The antenna subsystem of claim 1 wherein the electronically steerable transmit antenna lacks phase-shift circuits.

11. The antenna subsystem of claim 1 wherein the electronically steerable transmit antenna includes a holographic antenna.

12. A radar subsystem, comprising:

an electronically steerable transmit antenna including an array of transmit elements each configured to radiate a respective signal having a wavelength and each spaced apart from each adjacent one of the transmit elements by a respective first distance that is less than one half of the wavelength;

a beam-steering controller configured to cause the transmit antenna to form, from the radiated signals, a transmit beam pattern including a main transmit beam that occupies a transmit-beam region;

a sparse receive antenna including an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength; and

a radar processing unit configured to form, from the received signals, a receive beam pattern including a main receive beam within the transmit-beam region and including a first receive side lobe having a first amplitude and within a portion of the transmit-beam region having a second amplitude that is less than the first amplitude.

13. The radar subsystem of claim 12 wherein the radar processing unit is configured to form the receive beam pattern while the transmit antenna is forming the transmit beam pattern.

14. The radar subsystem of claim 12 wherein the radar processing unit is configured to form the receive beam pattern after the transmit antenna forms the transmit beam pattern.

15. The radar subsystem of claim 12 wherein:

the beam-steering controller is configured to cause the transmit antenna to form, from the radiated signals, the transmit beam pattern including a transmit-side-lobe peak at a first direction; and

the radar processing unit is configured to form, from the received signals, the receive beam pattern including a second-receive-side-lobe having a null at approximately the first direction.

16. The radar subsystem of claim 12 wherein:

the beam-steering controller is configured to cause the transmit antenna to form, from the radiated signals, the transmit beam pattern including a transmit-side-lobe null at a first direction; and

the radar processing unit is configured to form, from the received signals, the receive beam pattern including a second-receive-side-lobe peak at approximately the first direction.

17. A vehicle, comprising:

a radar subsystem, including

an electronically steerable transmit antenna including an array of transmit elements each configured to radiate a respective signal having a wavelength and each spaced apart from each adjacent one of the transmit elements by a respective first distance that is less than one half of the wavelength,

a beam-steering controller configured to cause the transmit antenna to form, from the radiated signals, a transmit beam pattern including a main transmit beam that occupies a transmit-beam region,

a sparse receive antenna including an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength, and

a radar processing unit configured

to form, from the received signals, a receive beam pattern including a main receive beam within the transmit-beam region and including a first receive side lobe having a first amplitude and within a portion of the transmit-beam region having a second amplitude that is less than the first amplitude, and

to generate data in response to a signal received over the main receive beam;

a drive assembly; and

a controller configured to control the drive assembly in response to the data.

18. The system of claim 17 wherein the drive assembly comprises:

a propulsion unit; and

a steering unit.

19. A method, comprising:

generating a transmit beam pattern using an electronically steerable antenna, the transmit beam including a main transmit beam that occupies a main-transmit-beam region; and

generating a receive beam pattern in response to a signal received by a sparse digital-beamforming antenna, the receive beam pattern including a main receive beam that occupies a main-receive-beam region within the main-transmit-beam region.

20. The method of claim 19 wherein:

the main-transmit-beam region is defined by the half-power beam width of the main transmit beam; and

the main-receive-beam region is defined by the half-power beam width of the main receive beam.

21. The method of claim 19 wherein generating the transmit beam pattern and the receive beam pattern includes generating the transmit beam pattern and the receive beam pattern at different times.

22. The method of claim 19 wherein generating the transmit beam pattern and the receive beam pattern includes generating the transmit beam pattern and the receive beam pattern simultaneously.

23. The method of claim 19 wherein generating the receive beam pattern includes generating the receive beam pattern to include main receive beams that each occupy a respective main-receive-beam region within the main-transmit-beam region.

24. A method, comprising:

generating a transmit beam pattern using an electronically steerable antenna including an array of transmit elements each configured to radiate a respective signal having a wavelength and each spaced apart from each adjacent one of the transmit elements by a respective distance that is less than one half of the wavelength, the transmit beam pattern including a transmit side-lobe region; and

generating a receive beam pattern in response to a signal received by a sparse digital-beamforming antenna, the receive beam pattern including a receive-side-lobe null approximately aligned with the transmit side-lobe region if the transmit side-lobe region is a peak of the receive beam pattern, and including a receive-side-lobe peak approximately aligned with the transmit side-lobe region if the transmit side-lobe region is a null of the receive beam pattern.

25. The method of claim 24 wherein generating the transmit beam pattern includes generating the transmit beam pattern using an electronically steerable antenna having two subsections that are offset from one another.

26. A tangible non-transitory medium storing instructions that, when executed by a computing circuit, cause the computing circuit, or another circuit under control of the computing circuit:

to generate a transmit beam pattern using an electronically steerable antenna, the transmit beam including a main transmit beam that occupies a main-transmit-beam region; and

to generate a receive beam pattern in response to a signal received by a sparse digital-beamforming antenna, the receive beam pattern including main receive beams that each occupy a respective main-receive-beam region within the main-transmit-beam region.

27. A tangible non-transitory medium storing instructions that, when executed by a computing circuit, cause the computing circuit, or another circuit under control of the computing circuit:

to generate a transmit beam pattern using an electronically steerable antenna including an array of transmit elements each configured to radiate a respective signal having a wavelength and each spaced apart from each adjacent one of the transmit elements by a respective distance that is less than one half of the wavelength, the transmit beam including a transmit side-lobe region; and

to generate a receive beam pattern in response to a signal received by a sparse digital-beamforming antenna, the receive beam pattern including a receive-side-lobe null approximately aligned with the transmit side-lobe region if the transmit side-lobe region constitutes a peak of the transmit beam pattern, and including a receive-side-lobe peak approximately aligned the transmit side-lobe region if the transmit side-lobe region constitutes a null of the transmit beam pattern.

28. A radar subsystem, comprising:

an electronically steerable transmit antenna including an array of transmit elements each configured to radiate a respective signal having a wavelength and each spaced apart from each adjacent one of the transmit elements by a respective first distance that is less than one half of the wavelength;

a beam-steering controller configured to cause the transmit antenna to form, from the radiated signals, a transmit beam pattern including a transmit side lobe;

a sparse receive antenna including an array of receive elements each configured to receive a respective signal having a wavelength and each spaced apart from each adjacent one of the receive elements by a respective first distance that is more than one half of the wavelength; and

a radar processing unit configured

to form, from the received signals, a receive beam pattern including a receive-side-lobe null approximately aligned with the transmit side lobe if the transmit side lobe is a peak of the transmit beam pattern, and

to form, from the received signals, a receive beam pattern including a receive-side-lobe peak approximately aligned with the transmit side lobe if the transmit side lobe is a null of the transmit beam pattern.

29. The radar subsystem of claim 28 wherein the electronically steerable transmit antenna includes:

a first transmit-antenna section having a first subarray of the transmit elements; and

a second transmit-antenna section having a second subarray of the transmit elements and offset from the first transmit-antenna section.