Wafer Probe Integration with Low-Profile Tuner
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Solution Overview
Problem
Current load and source pull testing methods for RF transistors face challenges in accurately determining impedance conditions due to insertion loss and reduced tuning ranges, particularly when connecting wafer probes to impedance tuners, which limits the ability to achieve optimal impedance matching for high-power microwave and millimeter-wave transistors.
Innovation Solution
A low-profile tuner design integrating a wafer-probe bracket extension with planarity control, allowing secure attachment of the wafer probe to the tuner without an RF cable, and utilizing a 3-axis positioner to match the tuner's angle with the coaxial connector of the wafer probe, thereby minimizing insertion loss and maximizing the tuning range while enabling precise planarity adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an RF cable is used to connect the wafer probe to the impedance tuner, then the connection is secure and stable, but insertion loss increases and tuning range is reduced
Solution Approach 1:
The patent removes the RF cable from the system entirely, extracting the problematic component that causes insertion loss. The wafer probe is connected directly to the impedance tuner test port through a bracket extension, eliminating the intermediate cable that introduces energy loss and limits tuning range.
Solution Approach 2:
The patent employs an asymmetric connection geometry where the wafer probe is mounted at a specific angle (typically 45 degrees) relative to the tuner body, allowing the probe to approach the test port from an optimized direction. This asymmetric arrangement minimizes the distance and number of interfaces between the probe and tuner, reducing insertion loss while maintaining secure connection.
2Loss of energy
If the tuner is positioned closer to the wafer probe, then insertion loss is reduced and tuning range is maximized, but planarity control becomes difficult
Solution Approach 1:
The patent divides the connection system into distinct functional segments: the tuner body, the bracket extension, and the wafer probe. The bracket acts as an intermediate element that provides both mechanical support and planarity adjustment capability. This segmentation allows the tuner to be positioned close to the probe while maintaining independent control over the probe's planarity through the bracket's adjustment mechanisms.
Solution Approach 2:
The patent incorporates dynamic adjustment capabilities into the bracket system, allowing planarity to be controlled and optimized. The bracket includes adjustment mechanisms (such as screws or movable elements) that enable fine-tuning of the probe's orientation and contact plane, ensuring optimal planarity even when the tuner is positioned close to the probe.
3Loss of energy
If a bracket extension is used to hold the wafer probe, then RF cable is eliminated and insertion loss is reduced, but secure attachment becomes challenging
Solution Approach 1:
The patent merges multiple functions into the bracket extension: mechanical support, positioning, planarity control, and electrical connection. The bracket is designed as an integrated component that combines the holder function with the alignment and securing mechanisms, eliminating the need for separate RF cable while maintaining secure and stable attachment of the wafer probe to the tuner.
Data Source
AI summary
Integrating a bracket with planarity adjustment holding a wafer probe securely, with a low-profile impedance tuner that is mounted on a 3-axis tuner positioner under an angle matching the angle of the wafer probe. The low-profile tuner has its tuning probe operating as close as physically possible within the distance of an RF adapter from the wafer-probe and is connected directly with the wafer-probe. This integration offers the maximum possible tuning range, while simultaneously offering planarity (THETA) control. It also eliminates the need for an extension RF cable between the instrument (tuner) and the wafer-probe, including a set of two coaxial adapters.