Counterbored Probe Holder Structure for Low-Loss High-Frequency Probing
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Solution Overview
Problem
Existing probe units fail to adequately minimize damping of high frequency signals, despite techniques for characteristic impedance matching and through holes, as they often increase reflection loss and do not sufficiently reduce damping.
Innovation Solution
A probe unit design featuring a probe holder with insulating counterbore portions around holder holes, a multilayered structure with different insulating materials, and a configuration of contact probes with plungers and coil springs to minimize signal damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If characteristic impedance matching techniques (air layers, insulating rings, porous insulating members) are used, then reflection loss is reduced, but insertion loss increases and damping of high frequency signals is not sufficiently minimized
Solution Approach 1:
The patent changes the physical structure from flat surface layers to three-dimensional counterbore portions with specific depth-to-diameter ratios. This geometric parameter change creates effective impedance control without the harmful effects of conventional approaches, achieving both low reflection loss and low insertion loss by optimizing the counterbore dimensions rather than relying on material porosity or air layers
Solution Approach 2:
The patent transitions from two-dimensional surface modifications (air layers, insulating rings) to three-dimensional counterbore structures drilled into the holder body. This dimensional change allows for more effective electromagnetic field control and impedance matching, reducing both reflection loss and insertion loss simultaneously by providing additional spatial degrees of freedom for field distribution
2Loss of energy
If through holes are provided around contact probes for power feeding loss reduction, then power feeding loss decreases, but the through holes have large mismatches and damping is not sufficiently reduced
Solution Approach 1:
The patent applies different structural qualities to different locations: counterbore portions are provided only around signal contact probes, while ground contact probes have different configurations. This localized quality differentiation optimizes impedance control where needed without introducing mismatches elsewhere, achieving power feeding loss reduction while maintaining signal integrity and minimizing damping
Solution Approach 2:
The counterbore portions act as intermediary structures between the contact probes and the holder body, providing gradual impedance transition rather than abrupt changes. This intermediary structure reduces both power feeding loss and signal damping by creating a smooth electromagnetic field transition zone, avoiding the large mismatches caused by direct through holes
Data Source
AI summary
A probe unit includes: a contact probe that comes into contact with, at both ends of a longitudinal length of the contact probe, each of electrodes that are contact targets; and a probe holder including a main body portion configured to hold the contact probe, the main body portion being insulating. The main body portion includes, formed therein: a holder hole configured to hold the contact probe inserted in the holder hole; and a counterbore portion drilled in at least part of an area around the holder hole, the area being on one of surfaces of the main body portion, the surfaces being near one end and another end of the contact probe, the counterbore portion having an inner wall surface that forms a hollow space and that is insulating.