Millimeter wave impedance matching structures

Patent metadata

Field	Value
Publication number	US-11289802-B2
Application number	US-201916413508-A
Country	US
Kind code	B2
Filing date	May 15, 2019
Priority date	Apr 8, 2019
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

An electronic device may be provided with a transceiver, a substrate, and antennas mounted to the substrate. The transceiver and antennas may convey signals between 10 GHz and 300 GHz. A radio-frequency connector may be mounted to the substrate. A coaxial cable may couple the transceiver to the connector. A stripline in the substrate may couple the connector to the antennas. Impedance matching structures may be embedded in the substrate for matching an impedance of the stripline to an impedance of the coaxial cable. The impedance matching structures may include a fence of conductive vias, landing pads, and a volume of the dielectric substrate defined by the fence of conductive vias and the landing pads. The impedance matching structures may be configured to perform impedance matching over a relatively wide bandwidth that includes the frequency band of operation for the antennas.

First claim

What is claimed is:

1. An antenna module configured to be coupled to a transceiver using a first transmission line, the antenna module comprising:
a dielectric substrate;
an antenna on the dielectric substrate and configured to convey radio-frequency signals at a frequency between 10 GHz and 300 GHz;
a second transmission line embedded in the dielectric substrate;
a radio-frequency connector mounted to the dielectric substrate, wherein the radio-frequency connector is configured to receive the first transmission line; and
impedance matching structures that are embedded in the dielectric substrate and that couple the second transmission line to the radio-frequency connector, the impedance matching structures comprising a fence of conductive vias that is coupled to a grounded body portion of the radio-frequency connector, wherein the impedance matching structures are configured to match an impedance of the first transmission line to an impedance of the second transmission line.

2. The antenna module defined in claim 1 , wherein the first transmission line comprises a coaxial cable.

3. The antenna module defined in claim 2 , wherein the second transmission line comprises a stripline.

4. The antenna module defined in claim 1 , wherein the second transmission line comprises a stripline.

5. The antenna module defined in claim 1 , wherein the fence of conductive vias is ring-shaped, and a volume of the dielectric substrate has a diameter defined by the ring-shaped fence of conductive vias.

6. The antenna module defined in claim 5 , further comprising a contact pad on a surface of the dielectric substrate, wherein the contact pad is coupled to a signal body portion of the radio-frequency connector.

7. The antenna module defined in claim 6 , wherein the second transmission line comprises signal traces in the dielectric substrate, the antenna module further comprising:
a conductive via that couples the signal traces to the contact pad.

8. The antenna module defined in claim 7 , wherein the impedance matching structures further comprise landing pads coupled to the conductive via, wherein the landing pads define at least part of the volume.

9. The antenna module defined in claim 1 , wherein the dielectric substrate comprises a first dielectric layer, a second dielectric layer, and a third dielectric layer, the second dielectric layer being interposed between the first and third dielectric layers, the antenna module further comprising:
first ground traces on the first dielectric layer;
signal traces on the second dielectric layer; and
second ground traces on the third dielectric layer, wherein the signal traces and at least part of the first and second ground traces form the second transmission line.

10. The antenna module defined in claim 9 , wherein the fence of conductive vias couple the first ground traces to the second ground traces and a volume of the first, second, and third dielectric layers is defined at least in part by the fence of conductive vias.

11. The antenna module defined in claim 10 , wherein the radio-frequency connector is mounted to the second ground traces.

12. The antenna module defined in claim 10 , further comprising:
a fourth dielectric layer interposed between the radio-frequency connector and the second ground traces; and
third ground traces on the fourth dielectric layer, wherein the fence of conductive vias is coupled to the third ground traces, the radio-frequency connector being mounted to the third ground traces.

13. Apparatus comprising:
a dielectric substrate;
an antenna on the dielectric substrate and configured to convey radio-frequency signals at a frequency between 10 GHz and 300 GHz;
a stripline having first ground traces, second ground traces, and signal traces, the signal traces being coupled to the antenna and extending between the first and second ground traces; and
impedance matching structures embedded in the dielectric substrate and coupled to the stripline, wherein the impedance matching structures are configured to match an impedance of the stripline to an impedance of a transmission line external to the dielectric substrate.

14. The apparatus defined in claim 13 , further comprising a contact pad at a surface of the dielectric substrate and a conductive via coupled to the contact pad and extending through the dielectric substrate, wherein
the signal traces are coupled to the conductive via.

15. The apparatus defined in claim 14 , further comprising:
a fence of conductive vias that couples the first ground traces to the second ground traces and that laterally surrounds the conductive via; and
a landing pad on the dielectric substrate and coupled to the conductive via at a location between the signal traces and the contact pad, wherein the impedance matching structures comprise the fence of conductive vias, the landing pad, and a volume of the dielectric substrate defined by the fence of conductive vias and the landing pad.

16. The apparatus defined in claim 15 , wherein a dielectric constant of the dielectric substrate within the volume, a width of the landing pad, and a diameter of the fence of conductive vias are selected to configure the impedance matching structures to match the impedance of the stripline to the impedance of the transmission line external to the dielectric substrate.

17. The apparatus defined in claim 16 , further comprising:
a radio-frequency connector mounted to the dielectric substrate and configured to receive the transmission line external to the dielectric substrate, wherein the transmission line external to the dielectric substrate comprises a coaxial cable, the radio-frequency connector comprising a signal body portion coupled to the contact pad and a grounded body portion coupled to the first ground traces by the fence of conductive vias.

18. Apparatus comprising:
a dielectric substrate;
ground traces on the dielectric substrate;
a radio-frequency connector on a surface of the dielectric substrate;
a coaxial cable coupled to the radio-frequency connector;
a stripline in the dielectric substrate;
a conductive via that couples a signal conductor of the stripline to the radio-frequency connector;
a landing pad in the dielectric substrate and coupled to the conductive via; and
a fence of conductive vias that couple the radio-frequency connector to the ground traces, wherein the fence of conductive vias runs around the conductive via and the landing pad, the landing pad and the fence of conductive vias defining a volume of the dielectric substrate that is configured to match an impedance of the stripline to an impedance of the coaxial cable.

19. The apparatus defined in claim 18 , further comprising:
additional ground traces in the dielectric substrate, wherein the fence of conductive vias couples the ground traces to the additional ground traces, and the signal conductor of the stripline extends between the ground traces and the additional ground traces.

Assignees

• Apple Inc

Inventors

• Paulotto Simone
• Edwards Jennifer M
• Rajagopalan Harish
• Avser Bilgehan

Classifications

• H05K1/113

  Via provided in pad; Pad over filled via · CPC title

• H05K2201/09609

  Via grid, i.e. two-dimensional array of vias or holes in a single plane · CPC title

• H01P5/02

  with invariable factor of coupling (H01P5/12 takes precedence {choke joints H01P1/04, H01P1/06}) · CPC title

• H01P1/045 Primary

  Coaxial joints · CPC title

• H01P5/085

  Coaxial-line/strip-line transitions · CPC title