Low elevation sidelobe antenna with fan-shaped beam

Patent metadata

Field	Value
Publication number	US-11670864-B2
Application number	US-202017136393-A
Country	US
Kind code	B2
Filing date	Dec 29, 2020
Priority date	Dec 29, 2020
Publication date	Jun 6, 2023
Grant date	Jun 6, 2023

Abstract

Example embodiments relate to low elevation side lobe antennas with fan-shaped beams. An example radar unit may include a radiating plate having a first side and a second side with an illuminator, a waveguide horn, a waveguide opening, and a radiating sleeve extending into the first side of the radiating plate. The waveguide opening is positioned on the first end of the first side and the radiating sleeve is positioned on the second end of the first side. The radar unit also includes a metallic cover coupled to the first side of the radiating plate such that the metallic cover and the radiating plate form waveguide structures. The waveguide horn is configured to receive, from an external source, electromagnetic energy provided through the waveguide opening via a first waveguide and provide a portion of the electromagnetic energy to the illuminator via a second waveguide such that the portion of the electromagnetic energy radiates off the illuminator and through the radiating sleeve into an environment of the radar unit as one or more radar signals.

First claim

What is claimed is:

1. A radar unit comprising: a radiating plate having a first side and a second side, wherein the radiating plate includes an illuminator, a waveguide horn, a waveguide opening, and a radiating sleeve that are formed into the first side of the radiating plate, wherein the waveguide opening is positioned on a first end of the first side and the radiating sleeve is positioned on a second end of the first side, and the first end of the first side is opposite the second end of the first side; and a metallic cover coupled to the first side of the radiating plate such that the metallic cover and the radiating plate form a plurality of waveguide structures and enclose the illuminator and the waveguide horn, wherein the illuminator has an arc-shape with a concave surface oriented toward the radiating sleeve and an end opening of the waveguide horn, and wherein, during radar signal transmission by the radar unit, the waveguide horn: receives, from an external source, electromagnetic energy provided through the waveguide opening via a first waveguide; and provides a portion of the electromagnetic energy out of the waveguide horn through the end opening of the waveguide horn and in a direct path toward the concave surface of the illuminator via a second waveguide such that the portion of the electromagnetic energy reflects off the concave surface of the illuminator and subsequently radiates through the radiating sleeve into an environment of the radar unit as one or more radar signals.

2. The radar unit of claim 1 , wherein the illuminator has a degree of curvature, and wherein the degree of curvature is configured to reduce a side lobe level of radar signals transmitted via the radar unit.

3. The radar unit of claim 2 , wherein the degree of curvature is based on a focus point of the waveguide horn.

4. The radar unit of claim 1 , wherein the waveguide horn is further configured to:
receive reflections corresponding to the one or more radar signals from the environment, wherein the reflections: (i) traverse through the radiating sleeve toward the illuminator and (ii) reflect off the illuminator and into the waveguide horn; and
provide, via the first waveguide, the reflections through the waveguide opening and to the external source.

5. The radar unit of claim 1 , wherein the waveguide horn includes a fray opening.

6. The radar unit of claim 1 , wherein a top portion of the illuminator extends parallel to the first waveguide.

7. The radar unit of claim 1 , wherein the external source is a printed circuit board (PCB) configured to supply electromagnetic energy.

8. The radar unit of claim 1 , wherein the metallic cover is flat, and where the illuminator, the waveguide horn, the waveguide opening, and the radiating sleeve are etched a threshold depth into the radiating plate.

9. The radar unit of claim 1 , further comprising:
a second radiating plate having a first side and a second side, wherein the first side of the second radiating plate includes a second illuminator, a second waveguide horn, a second waveguide opening, and a second radiating sleeve that extend into the first side of the second radiating plate, and
wherein the first side of the second radiating plate is coupled to the second side of the radiating plate such that the radiating plate and the second radiating plate form a second plurality of waveguide structures.

10. The radar unit of claim 9 , wherein the second waveguide horn is configured to:
receive reflections corresponding to the one or more radar signals from the environment, wherein the reflections: (i) traverse through the second radiating sleeve toward the second illuminator and (ii) reflect off the second illuminator and into the second waveguide horn; and
provide, via a given waveguide from the second plurality of waveguide structures, the reflections through the second waveguide opening and to the external source.

11. The radar unit of claim 1 , wherein the first waveguide extends in a direction along a length of the radiating plate.

12. A vehicle radar system comprising: a plurality of radar units coupled to a vehicle and configured to use radar signals to measure an environment of the vehicle, wherein at least one radar unit from the plurality of radar units comprises: a radiating plate having a first side and a second side, wherein the radiating plate includes an illuminator, a waveguide horn, a waveguide opening, and a radiating sleeve that are formed into the first side of the radiating plate, wherein the waveguide opening is positioned on a first end of the first side and the radiating sleeve is positioned on a second end of the first side, and the first end of the first side is opposite the second end of the first side; and a metallic cover coupled to the first side of the radiating plate such that the metallic cover and the radiating plate form a plurality of waveguide structures and enclose the illuminator and the waveguide horn, wherein the illuminator has an arc-shape with a concave surface oriented toward the radiating sleeve and an end opening of the waveguide horn, and wherein, during radar signal transmission by the at least one radar unit, the waveguide horn receives, from an external source, electromagnetic energy provided through the waveguide opening via a first waveguide; and
provides a portion of the electromagnetic energy out of the waveguide horn through the end opening of the waveguide horn and in a direct path toward the concave surface of the illuminator via a second waveguide such that the portion of the electromagnetic energy reflects off the concave surface of the illuminator and subsequently radiates through the radiating sleeve into the environment as one or more radar signals.

13. The vehicle radar system of claim 12 , wherein the waveguide horn is further configured to:
receive reflections corresponding to the one or more radar signals from the environment, wherein the reflections: (i) traverse through the radiating sleeve toward the illuminator and (ii) reflect off the illuminator and into the waveguide horn; and
provide, via the first waveguide, the reflections through the waveguide opening and to a processor.

14. The vehicle radar system of claim 13 , wherein the processor is configured to:
receive the reflections from the at least one radar unit;
receive a plurality of reflections corresponding to respective radar signals transmitted by one or more additional radar units from the vehicle radar system;
perform a fusion process using the reflections from the at least one radar unit and the plurality of reflections corresponding to respective radar signals transmitted by one or more additional radar units; and
determine a two dimensional (2D) map of the environment based on the fusion process, wherein the 2D map indicates information corresponding to one or more objects in the environment.

15. The vehicle radar system of claim 12 , wherein the illuminator of the at least one radar unit has a degree of curvature, and wherein the degree of curvature is configured to reduce a side lobe level of radar signals transmitted via the at least one radar unit.

16. The vehicle radar system of claim 15 , wherein the degree of curvature is based on a focus point of the waveguide horn such that the one or more radar signals have a fan-shaped beam that includes a plus/minus 2.5 degrees on an elevation plane.

17. The vehicle radar system of claim 12 , wherein the plurality of radar units coupled to the vehicle further comprises:
a second radar unit comprising:
a plurality of radiating plates, wherein each radiating plate i

Assignees

• Waymo Llc

Inventors

• Lim Edwin
• Campbell Timothy
• Markel Matthew

Classifications

• H01Q19/138 Primary

  Parallel-plate feeds, e.g. pill-box, cheese aerials · CPC title

• H01Q13/02

  Waveguide horns · CPC title

• H01Q1/3275

  mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk · CPC title

• H01Q5/55

  for horn or waveguide antennas · CPC title

• H01Q13/0233

  Horns fed by a slotted waveguide array (biconical horns H01Q13/06) · CPC title