Substrate-Integrated Waveguide Transition for Millimeter-Wave Coupling
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Solution Overview
Problem
High frequency integrated circuits (ICs) face challenges in efficiently coupling millimeter-wave signals due to the complex and costly manufacturing processes required for traditional printed circuit board (PCB) waveguide transitions, which are not compatible with high volume and low cost production.
Innovation Solution
The integration of a substrate with a waveguide transition that includes a back short, formed by multiple layers of metal and dielectric material, with ground-stitching vias defining the waveguide cross-section, allowing for standard PCB manufacturing methods and efficient coupling of millimeter-wave signals to external waveguides without additional post-processing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional PCB waveguide transition manufacturing methods are used, then waveguide coupling is achieved, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent combines the waveguide structure directly with the PCB substrate by etching the waveguide path through the PCB layers and forming conductive walls using standard PCB manufacturing techniques. This merging eliminates the need for separate waveguide components and manual assembly, reducing manufacturing complexity while maintaining coupling reliability
Solution Approach 2:
The PCB substrate serves multiple functions: it acts as both the circuit board for planar transmission lines and as the waveguide structure itself. The same PCB manufacturing process produces both the transmission lines and the waveguide, enabling high-volume production without additional specialized steps
2Reliability
If traditional PCB waveguide transition manufacturing methods are used, then waveguide coupling is achieved, but production volume and cost effectiveness decrease
Solution Approach 1:
By integrating the waveguide structure into the PCB substrate using standard etching and plating processes, the invention enables waveguide transitions to be manufactured using automated PCB production lines. This eliminates manual probe positioning and attachment steps, significantly increasing production volume capability
Solution Approach 2:
The waveguide is segmented into discrete PCB layers with conductive walls formed by standard plating processes. This segmentation allows each layer to be manufactured independently using automated PCB processes, enabling high-volume production while maintaining assembly reliability
3Reliability
If manual probe positioning and attachment is used, then signal coupling is achieved, but manufacturing precision and consistency suffer
Solution Approach 1:
The probe structure is merged with the PCB substrate itself, with the transmission line ending directly at the waveguide opening in the substrate. This eliminates the need for separate probe components and manual positioning, achieving consistent signal coupling through automated PCB manufacturing precision
Solution Approach 2:
The waveguide opening and conductive wall structures are pre-formed during standard PCB manufacturing before final assembly. This preliminary formation of precise geometric features ensures consistent signal coupling without requiring subsequent manual probe positioning operations
Data Source
AI summary
In described examples, an integrated waveguide transition includes a substrate with a waveguide side and an opposing waveguide termination side. A first layer of metal covers a portion of the waveguide side, a second layer of metal is separated from the first layer of metal by a first layer of dielectric, and a third layer of metal covers a portion of the waveguide termination side and is separated from the second layer of metal by a second layer of dielectric. A substrate waveguide perpendicular to a plane of the substrate extends from the waveguide side to the waveguide termination side; and a length and a width of the substrate waveguide is defined by a fence of ground-stitching vias that short the first layer of metal and the second layer of metal to a plate of the third layer of metal that forms a back short.