PCB tuning for waveguide antennae
RADAR sensor assemblies/modules, particularly those for vehicles. In some embodiments, the assembly may comprise a waveguide comprising a waveguide groove defined by opposing waveguide groove structures. An antenna structure may be operably coupled with the waveguide. A printed circuit board may be operably coupled with the waveguide and may comprise an electrically conductive top layer, an electrically conductive bottom layer, and a substrate positioned in between the electrically conductive top layer and the electrically conductive bottom layer. The electrically conductive top layer may comprise an opening exposing the substrate, which opening may extend along the waveguide groove in between the opposing waveguide groove structures. This configuration may allow for various parameters of the printed circuit board to be modified to tune a performance of a sensor/antenna.
1. A waveguide antenna assembly, comprising:
a waveguide comprising a waveguide groove defined by opposing waveguide groove structures;
an antenna structure operably coupled with the waveguide; and
a printed circuit board operably coupled with the waveguide, wherein the printed circuit board comprises an electrically conductive top layer, an electrically conductive bottom layer, and a substrate positioned in between the electrically conductive top layer and the electrically conductive bottom layer, and wherein the electrically conductive top layer comprises an opening exposing the substrate, wherein the opening extends along the waveguide groove in between the opposing waveguide groove structures.
2. The waveguide antenna assembly of claim 1 , wherein the waveguide and antenna structure are configured to be coupled with a plurality of different printed circuit boards to adjust one or more performance characteristics of the waveguide antenna assembly by adjusting one or more parameters of a printed circuit board to which the waveguide and antenna structure are coupled.
3. The waveguide antenna assembly of claim 2 , wherein the one or more parameters comprises at least one of a dielectric constant of the substrate, a width of the opening exposing the substrate, a length of the opening exposing the substrate, and a thickness of the substrate.
4. The waveguide antenna assembly of claim 3 , further comprising a cavity formed in the printed circuit board, wherein the cavity is at least partially defined by the electrically conductive bottom layer and on opposing sides of the cavity by one or more electrically conductive structures coupling the electrically conductive bottom layer with the electrically conductive top layer.
5. The waveguide antenna assembly of claim 4 , wherein the one or more electrically conductive structures comprises a row of adjacent vias defining a via wall.
6. The waveguide antenna assembly of claim 4 , wherein the one or more parameters further comprises at least one of a width of the cavity and a length of the cavity.
7. The waveguide antenna assembly of claim 2 , wherein the waveguide and the antenna structure are both formed in a single, unitary structure.
8. The waveguide antenna assembly of claim 7 , wherein the single, unitary structure comprises at least one of a diecast waveguide antenna block and an injection molded waveguide antenna block.
9. The waveguide antenna assembly of claim 1 , wherein the opposing waveguide groove structures comprise one or more opposing rows of posts.
10. The waveguide antenna assembly of claim 1 , further comprising an array of electromagnetic band-gap structures formed within the opening.
11. The waveguide antenna assembly of claim 10 , wherein the array of electromagnetic band-gap structures comprises a plurality of electrically conductive rectangular structures positioned on a top surface of the substrate and comprising a via extending through the substrate to couple with the electrically conductive bottom layer of the printed circuit board.
12. The waveguide antenna assembly of claim 11 , wherein the waveguide and antenna structure are configured to be coupled with a plurality of different printed circuit boards to adjust one or more performance characteristics of the waveguide antenna assembly by adjusting one or more parameters of a printed circuit board to which the waveguide and antenna structure are coupled, and wherein the one or more parameters comprises at least one of a dielectric constant of the substrate, a width of the opening exposing the substrate, a length of the opening exposing the substrate, a thickness of the substrate, and a pattern of the array of electromagnetic band-gap structures.
13. A vehicle sensor antenna assembly, comprising:
a waveguide block comprising:
a waveguide groove;
an antenna slot extending along an axis of the waveguide groove, wherein the antenna slot is configured to deliver electromagnetic radiation therethrough as part of a signal for a vehicle sensor; and
a printed circuit board coupled with the waveguide block and forming a wall of the waveguide groove, wherein the printed circuit board comprises:
a first metallic layer;
a second metallic layer;
a substrate positioned in between the first metallic layer and the second metallic layer; and
an elongated opening formed in the first metallic layer adjacent to the waveguide groove to expose the substrate therethrough.
14. The vehicle sensor antenna assembly of claim 13 , wherein the printed circuit board is removably coupleable to the waveguide block to allow any of a plurality of other printed circuit boards having differing characteristics used to tune a performance of the vehicle sensor by changing the characteristics of the printed circuit board alone.
15. The vehicle sensor antenna assembly of claim 13 , further comprising a dielectric cavity formed in the substrate.
16. The vehicle sensor antenna assembly of claim 15 , wherein the dielectric cavity is formed, at least in part, by a first row of conductive vias extending between the first metallic layer and the second metallic layer on a first side of the dielectric cavity and a second row of conductive vias extending between the first metallic layer and the second metallic layer along a second side of the dielectric cavity opposite the first side of the dielectric cavity.
17. The vehicle sensor antenna assembly of claim 16 , wherein the printed circuit board is removably coupleable to the waveguide block to allow any of a plurality of other printed circuit boards having differing tuning characteristics used to tune a performance of the vehicle sensor by changing the tuning characteristics of the printed circuit board alone, and wherein the tuning characteristics comprise a dielectric constant of the substrate, a width of the elongated opening exposing the substrate, a length of the elongated opening exposing the substrate, a thickness of the substrate, a width of the dielectric cavity, and a length of the dielectric cavity.
18. The vehicle sensor antenna assembly of claim 13 , wherein the waveguide groove is formed by one or more opposing rows of posts.
19. The vehicle sensor antenna assembly of claim 13 , further comprising an array of electromagnetic band-gap structures formed in the elongated opening.
20. The vehicle sensor antenna assembly of claim 19 , wherein the array of electromagnetic band-gap structures comprises a mushroom shape comprising an enlarged head protruding from a surface of the substrate opposite from the second metallic layer and a relatively narrower stem extending through the substrate to the second metallic layer.