Pre-matching Module for Millimeter-Wave Impedance Tuning
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Solution Overview
Problem
Current mechanical impedance tuners for millimeter-wave frequencies are cumbersome and difficult to integrate on wafer probe stations due to their complex mechanics, limiting the tuning range and causing significant insertion loss, which prevents matching of high-power transistors with small internal impedance.
Innovation Solution
A compact manual pre-matching module is integrated into the extended slabline using a rack-and-pinion mechanism and an eccentrically rotating disc probe, eliminating the need for a long vertical axis and allowing closer proximity to the wafer probe, minimizing insertion loss and increasing the tuning range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional mechanical impedance tuner with long vertical axis and micrometric screw is used, then the tuning mechanism provides sufficient thread engagement to avoid wobbling and backlash, but the tuner becomes cumbersome and difficult to integrate on wafer probe stations
Solution Approach 1:
The patent divides the tuning mechanism into two independent rotational movements: azimuthal rotation for phase control and elevation rotation for amplitude control. This segmentation replaces the single complex vertical axis mechanism with two simpler rotational axes, reducing mechanical complexity while maintaining tuning stability through precise angular control of the probe position.
Solution Approach 2:
The patent transitions from a single vertical dimension of adjustment to a two-dimensional angular control system using spherical coordinates (azimuth and elevation angles). This dimensional change allows the probe to reach any position in three-dimensional space through rotational movements, eliminating the need for a long vertical axis with extensive thread engagement while achieving the same positioning precision.
2Ease of operation
If the tuner is placed farther from the wafer probe, then there is less mechanical conflict with the microscope and other components, but the insertion loss increases significantly
Solution Approach 1:
The patent uses three-dimensional angular positioning (azimuth and elevation) to place the tuning probe in optimal spatial locations that are close to the wafer probe electrically while maintaining mechanical accessibility. The spherical coordinate system enables the probe to navigate around obstacles like the microscope while staying within the electromagnetic near-field region, minimizing insertion loss through precise angular control rather than simple linear displacement.
Solution Approach 2:
The patent implements dynamically adjustable angular positions for the tuning probe, allowing real-time optimization of the probe's location relative to the wafer probe. This dynamic positioning enables the system to adapt to different measurement configurations and minimize insertion loss by placing the probe at the optimal distance and angle, rather than using a fixed position that must compromise between accessibility and electrical performance.
3Adaptability or versatility
If the tuning range is extended to match high-power transistors with small internal impedance, then the conjugate complex internal impedance can be reached, but the passive tuner cannot power-match these devices due to insertion loss
Solution Approach 1:
The patent applies pre-matching transformation through the first tuning probe before the signal reaches the main impedance tuner. This preliminary action creates an optimized impedance transformation path that reduces the burden on the passive tuner, enabling it to achieve power-matching for high-power transistors with small internal impedance. The pre-matching probe prepares the signal by creating a virtual source with transformed impedance characteristics, allowing the subsequent passive tuning stage to operate more effectively with reduced insertion loss.
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 enhances the tuning range and reduces insertion loss, enabling the matching of high-power transistors with small internal impedance by minimizing mechanical conflicts and optimizing the position of the pre-matching module near the wafer probe, thus improving the accuracy of millimeter-wave impedance matching.
Implementation Method 1
A compact manual pre-matching module is integrated into the extended slabline using a rack-and-pinion mechanism
Implementation Method 2
an eccentrically rotating disc probe, eliminating the need for a long vertical axis
Data Source
AI summary
An integrated manual pre-matching module for on-wafer load pull tuner operation uses a mobile rack and a rotating reflective probe, mounted and sliding on the tuner slabline extension.Both the tuning probe position and immersion into the slabline are controlled using sidewise mounted easily accessible knobs. The low profile of the module does not conflict with the microscope and allows integrating on the extended slabline of the tuner in immediate proximity of the wafer probe, thus minimizing any additional insertion loss and maximizing tuning range. Manual handling of the pre-matching tuning module is easy and efficient without disturbing the on-wafer load pull operations.