# US 11,757,166 B2 · Surface-mount waveguide for vertical transitions of a printed circuit board

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- Number: US 11,757,166 B2
- Document ID: US11757166B2
- Status: Granted
- Kind: B2
- Application number: 17/155,949
- Filed: 2021-01-22
- Published: 2022-05-12
- Granted: 2023-09-12
- Earliest claimed: 2020-11-10
- Assignees: Aptiv Technologies AG
- Applicants: Aptiv Technologies Limited
- Inventors: Biswadeep Das Gupta; Sara J. Cavazos; Kurt E. Gilbertson
- Web page: https://patentgrep.com/patent/US11757166B2

## CPC

- H01P 5/107: Hollow-waveguide/strip-line transitions
- H01Q 1/2283: {mounted in or on the surface of a semiconductor substrate as a chip-type antenna or integrated with other components into an IC package}
- H01Q 1/3233: {particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems}
- H05K 1/181: associated with surface mounted components
- H05K 2201/037: Hollow conductors, i.e. conductors partially or completely surrounding a void, e.g. hollow waveguides
- H05K 2201/09985: Hollow waveguide combined with printed circuit
- H05K 2201/10098: Components for radio transmission, e.g. radio frequency identification [RFID] tag, printed or non-printed antennas
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS

## Abstract

Waveguide assemblies are described that utilize a surface-mount waveguide for vertical transitions of a printed circuit board (PCB). The surface-mount waveguide enables low transmission-loss (e.g., increased return-loss bandwidth) by utilizing a waveguide cavity positioned over a plated slot to efficiently transfer electromagnetic energy from one side of the PCB to another side. The waveguide cavity is designed to excite two resonant peaks of the EM energy to reduce a return-loss of power and increase power delivered to an antenna while supporting a high bandwidth of EM energy. Furthermore, the surface-mount waveguide does not require precise fabrication often required for vertical transitions, allowing the surface-mount waveguide to be compatible with low-cost PCB materials (e.g., hybrid PCB stack-ups).

## Claims

### Claim 1

A waveguide assembly comprising:
a printed circuit board (PCB) comprising:
at least one PCB layer that includes a first surface and a second surface positioned opposite and in parallel with the first surface;
a plated slot configured to channel an electromagnetic (EM) energy from a planar dimension in parallel with the first surface to a vertical dimension that is orthogonal to the planar dimension, the plated slot comprising an opening surrounded by a conductive material to enable electrical connections between the first surface and the second surface, the opening configured to transfer the EM energy between the first surface and the second surface; and
a waveguide cavity mounted directly on the first surface and positioned over the plated slot, the waveguide cavity being hollow and configured to perform impedance matching of the EM energy while guiding the EM energy from the first surface to the second surface via the plated slot, the waveguide cavity comprising:
a bottom surface configured to be open, the bottom surface mounted directly on the first surface of the PCB;
a taper section configured to taper a height of the waveguide cavity, the height of the waveguide cavity gradually increasing at a taper angle from a cavity front to a cavity middle, the height of the waveguide cavity being tapered to enable impedance matching of the EM energy; and
a resonant section connected to the taper section at the cavity middle, the resonant section being rectangular in shape.

### Claim 2 (depends on 1)

The waveguide assembly of claim 1, further comprising at least one antenna mounted on the second surface of the PCB, wherein the waveguide assembly is configured to:
direct the EM energy from the first surface of the PCB to the at least one antenna; and
transmit the EM energy using the at least one antenna.

### Claim 3 (depends on 1)

The waveguide assembly claim 1, wherein:
the waveguide cavity further comprises a drawn-waveguide cavity;
the drawn-waveguide cavity is formed using a sheet metal drawing process; and
the sheet metal drawing process comprises pulling a metal material to form the drawn-waveguide cavity.

### Claim 4 (depends on 1)

The waveguide assembly of claim 1, wherein:
the waveguide cavity further comprises a stamped-waveguide cavity;
the stamped-waveguide cavity is formed using a sheet metal stamping process; and
the sheet metal stamping process comprises pressing a metal material with a stamping press to form the stamped-waveguide cavity.

### Claim 5 (depends on 1)

The waveguide assembly claim 1, wherein the waveguide assembly is configured to:
enable operations of a radar system wherein the radar system is configured to determine a proximity, an angle, or a velocity of at least one object; and
mount to an automobile.

### Claim 6 (depends on 1)

The waveguide assembly of claim 1, wherein the waveguide cavity further comprises an entry opening positioned at the cavity front, the entry opening configured to:
enable the EM energy to enter the waveguide cavity via a microstrip line, the microstrip line aligned orthogonal to and centered about the entry opening, the microstrip line comprising a conductive material and configured to enable electrical connections;
excite a mode of the EM energy; and
generate a first resonant peak configured to increase a return-loss bandwidth, wherein an increase in the return-loss bandwidth is correlated with an increase in power supplied to at least one antenna.

### Claim 7 (depends on 6)

The waveguide cavity of claim 6, wherein a height of the entry opening is configured to:
change an amplitude of the first resonant peak; and
change the return-loss bandwidth.

### Claim 8 (depends on 6)

The waveguide assembly of claim 6, wherein:
a resonant-cavity distance is defined from a center of the plated slot to a back of the waveguide cavity;
the resonant-cavity distance is configured to generate a second resonant peak; and
the second resonant peak is configured to increase the return-loss bandwidth.

### Claim 9 (depends on 6)

The waveguide assembly of claim 6, wherein:
the PCB further comprises an integrated circuit (IC) mounted on the first surface of the PCB;
the IC is electrically connected to the waveguide cavity via the microstrip line; and
the microstrip line is further configured to enable transport of the EM energy between the waveguide cavity and the IC.

### Claim 10 (depends on 9)

The waveguide assembly of claim 9, wherein:
the IC is a monolithic microwave integrated circuit (MMIC) configured to operate at frequencies in a microwave range; and
the MMIC is heat sunk into the first surface of the PCB, configured to distribute thermal energy that is generated at least in part by the MMIC.

### Claim 11 (depends on 1)

The waveguide assembly of claim 1, wherein the PCB further comprises:
a top layer; and
remaining layers comprising at least one layer, the remaining layers aligned in parallel and at least partially in contact, the top layer aligned in parallel with and at least partially in contact with the remaining layers.

### Claim 12 (depends on 11)

The waveguide assembly of claim 11, wherein the PCB further comprises multiple vias, the multiple vias comprising:
a vias opening in the at least one PCB layer, the vias opening lined with a conductive material, the vias opening configured to electrically connect layers of the PCB; and
at least one of the following:
a thru via configured to electrically connect all of the layers of the PCB, the vias opening located on both the first surface of the PCB and the second surface of the PCB; and
a blind via configured to electrically connect at least one of the layers of the PCB but not all of the layers of the PCB, the vias opening located on either the first surface of the PCB or the second surface of the PCB but not both.

### Claim 13 (depends on 12)

The waveguide assembly of claim 12, wherein:
the taper section comprises a plurality of vias;
the plurality of vias is positioned on the bottom surface;
the plurality of vias comprises at least one of the following:
the thru via; or
the blind vias; and
the plurality of vias is configured to enable:
excitation of a mode of the EM energy; and
generation of a first resonant peak.

### Claim 14 (depends on 11)

The waveguide assembly of claim 11, wherein:
the PCB further comprises a hybrid PCB stack-up comprising the top layer and the remaining layers;
the top layer comprises a first material distinct from a second material of the remaining layers; and
the first material comprises a dielectric material.

### Claim 15 (depends on 14)

The waveguide assembly of claim 14, wherein the second material includes one or more of the following:
porcelain;
mica;
glass;
plastic;
metal oxides; and
polymers.

### Claim 16 (depends on 1)

The waveguide assembly of claim 1, wherein the waveguide cavity further comprises a metal material configured to enable transport of the EM energy from the cavity front to the plated slot.

### Claim 17 (depends on 1)

The waveguide assembly of claim 1, wherein the PCB further comprises a cast-waveguide cavity located within the at least one PCB layer, the cast-waveguide cavity comprises:
a cast heatsink configured to distribute thermal energy via a heat-spreader wall that surrounds the cast heatsink;
the waveguide cavity further configured to be positioned within the cast heatsink; and
a gasket positioned around the bottom surface and in contact with the first surface of the PCB, the gasket configured to enable:
compression of the gasket; and
electrical connections including transport of the EM energy.

### Claim 18 (depends on 17)

The waveguide assembly of claim 17, wherein the waveguide cavity comprises an electrically conductive plastic material configured to enable electrical connections.

### Claim 19 (depends on 17)

The waveguide assembly of claim 17, wherein the waveguide cavity comprises a plated plastic material configured to enable electrical connections, the plated plastic material comprising a plastic material coated in metal.

### Claim 20 (depends on 8)

The waveguide assembly of claim 8, wherein the resonant-cavity distance is equal to three-quarters of a wavelength of the EM energy.