Integrated Waveguide Transition in Multilayer Packages for Low-Loss mmWave
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Solution Overview
Problem
Designing waveguide transition devices for high-frequency signals, such as millimeter wave signals, is challenging due to impedance matching and low loss requirements, especially with conventional PCB materials, which are costly and difficult to implement effectively beyond 30 GHz frequencies, and require substantial device and board area.
Innovation Solution
A multilayer build-up package substrate with trace conductor layers and connection conductor layers is formed, allowing for the creation of a waveguide transition with an input port at the board side surface and sub-transitions that couple signals to a coplanar waveguide on the device side surface, using additive manufacturing to achieve impedance matching and reduce signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional PCB materials and waveguide transition devices are used for high-frequency signals, then signal transmission is achieved, but impedance matching and low loss requirements become increasingly difficult to meet beyond 30 GHz frequencies
Solution Approach 1:
The patent transitions from conventional two-dimensional PCB surface mounting to a three-dimensional multilayer substrate structure. The waveguide transition device is formed within multiple layers of the substrate, utilizing vertical stacking to achieve impedance matching and signal coupling. This dimensional change enables compact integration while maintaining high-frequency performance beyond 30 GHz.
Solution Approach 2:
The patent employs composite substrate structures combining multiple dielectric layers with embedded conductive elements. The multilayer substrate integrates different material properties to achieve impedance control, signal isolation, and mechanical support, resolving the design difficulties of conventional single-material PCB approaches at millimeter wave frequencies.
2Reliability
If custom PCB transition devices with required performance are designed, then low impedance and low loss goals are met, but cost increases significantly
Solution Approach 1:
The patent merges the waveguide transition function with the substrate structure itself. Instead of using separate PCB materials and mounting discrete transition devices, the substrate is formed with integrated conductor layers and dielectric materials that collectively provide the waveguide transition functionality. This consolidation reduces component count and manufacturing complexity while maintaining performance.
Solution Approach 2:
The multilayer substrate serves multiple functions simultaneously: it provides mechanical support, electrical grounding, signal transmission, and waveguide transition. The same substrate structure that supports the semiconductor device also forms the impedance-controlled transition path, eliminating the need for specialized expensive PCB materials and reducing overall system cost.
3Reliability
If conventional approaches with separate transition devices and antennas are used, then signal coupling is achieved, but substantial device and board area is required
Solution Approach 1:
The patent implements a nested structure where the waveguide transition is embedded within the substrate layers, and the semiconductor device is mounted within the same substrate structure. The conductor layers are nested vertically through multiple substrate layers, creating a compact three-dimensional arrangement that provides full signal coupling functionality in a minimal footprint area.
Solution Approach 2:
The patent utilizes the vertical dimension through multilayer stacking to achieve signal coupling without increasing planar area. Conductor paths extend through multiple layers of the substrate, allowing complex signal routes and impedance transformations to be achieved within the thickness of the package rather than spreading out on the board surface.
Data Source
AI summary
An example device includes: a multilayer build-up package substrate including trace conductor layers spaced from one another by dielectric material, and further including connection conductor layers coupling portions of the trace conductor layers through dielectric material, the multilayer build-up package substrate having a device side surface with one of the trace conductor layers and an opposing board side surface with one of the connection conductor layers; and a waveguide transition formed from the multilayer build-up package substrate, the waveguide transition having an input port formed from the connection conductor layer on the board side surface, and having at least two sub-transitions spaced laterally from one another, the at least two sub-transitions to couple a signal from the input port through the trace conductor layers and the connection conductor layers to a coplanar waveguide formed from the trace conductor layer on the device side surface.