MMIC Package Launcher for Direct Differential-to-Waveguide Transition
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Solution Overview
Problem
Existing packaging techniques for monolithic microwave integrated circuits (MMICs) face challenges in efficiently transitioning differential signals from the die to waveguide mode, leading to signal loss and reduced bandwidth due to long transmission lines and galvanic connections.
Innovation Solution
A packaged semiconductor device with a package substrate comprising multiple metal layers and conductive vias, featuring resonant slot openings and aligned vias to transition signals from differential mode to waveguide mode directly, reducing ohmic losses and allowing for compact, low-loss signal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional galvanic connections with intermediate transitions are used, then reliable signal transmission is achieved, but transmission line length increases causing signal loss and reduced bandwidth
Solution Approach 1:
The patent extracts and eliminates the intermediate single-ended transition stage from the traditional differential-to-waveguide transition path. By directly coupling differential pillars to waveguide mode through resonant slots, the design removes unnecessary transmission line segments and intermediate conversions, thereby reducing signal loss while maintaining transmission reliability.
Solution Approach 2:
The patent employs asymmetric resonant slot geometries (including H-shaped and cross-shaped configurations) that are optimized for direct differential-to-waveguide mode coupling. These asymmetric slot designs enable efficient field transformation from differential mode to waveguide fundamental mode, reducing the need for long symmetric transmission lines and minimizing signal attenuation.
2Reliability
If traditional packaging with intermediate transitions is used, then robust connection is achieved, but device size increases
Solution Approach 1:
The patent merges the differential signal transmission function and waveguide mode launch function into a single integrated structure. The resonant slots directly couple the differential pillars to the waveguide mode, eliminating the need for separate intermediate transition sections and reducing overall package volume while maintaining connection robustness.
Solution Approach 2:
The patent transitions from planar differential transmission lines to three-dimensional waveguide mode propagation through vertically stacked resonant slots. This dimensional transition allows compact integration by utilizing the vertical dimension for field transformation, reducing the horizontal footprint and overall package size.
3Loss of energy
If resonant slot openings are introduced for direct mode transition, then signal loss is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes resonant slot parameters (dimensions, positions, and geometries) to achieve direct differential-to-waveguide mode coupling with minimal ohmic loss. By carefully tuning slot lengths, widths, and spacing, the design achieves efficient field transformation while maintaining compatibility with standard PCB fabrication processes, thus managing manufacturing complexity.
4Reliability
If multiple metal layers with vias are used for mode transition, then signal integrity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent designs the resonant slots and via structures to serve multiple functions simultaneously: providing electrical connection, defining resonant frequencies, and enabling field transformation. This multi-functionality reduces the need for additional dedicated alignment features and simplifies manufacturing tolerances while maintaining signal integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a compact, low-loss transition from die to waveguide, enabling wide bandwidth and reducing signal losses, particularly suitable for millimeter or microwave signals, by transitioning signals directly to waveguide mode without intermediate single-ended transitions.
Implementation Method 1
the first metal layer comprises a resonant slot opening therethrough between the pair of pillars; wherein the resonant slot opening and the respective openings in the second, third and fourth metal layers are configured to transition the IO signal between the differential mode and a waveguide fundamental mode of propagation
Implementation Method 2
the resonant slot opening and the respective openings in the second, third and fourth metal layers are configured to transition the IO signal between the differential mode and a waveguide fundamental mode of propagation
Data Source
AI summary
Disclosed is a packaged semiconductor device, comprising: an MMIC device comprising a semiconductor die and having a differential IO; and a package substrate comprising dielectric between each of at least first through fourth metal layers, and electrically conductive vias between the metal layers; wherein the package substrate is connected to the MMIC device by a plurality of pillars between the MMIC device and the first metal layer, including a pair of the pillars which connect the differential IO to the first metal layer; wherein the first metal layer comprises a resonant slot opening therethrough between the pair of pillars; and wherein the second through fourth metal layers each comprise an opening therethrough, wherein the openings are configured to transition the IO signal between a differential mode and a waveguide fundamental mode of propagation at the fourth metal layer. A corresponding assembly further comprising a PCB is also disclosed.