High Frequency Probe Shielding for Crosstalk Reduction
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Solution Overview
Problem
Current probe measurement systems for high-frequency applications, such as microwave frequencies, face challenges with signal reflection, inductive losses, and cross-talk due to the length of conductive interconnections acting as antennas, leading to unsatisfactory performance and increased electromagnetic fields.
Innovation Solution
A high-frequency probe design with minimized conductor length and integrated shielding, where contact tips are positioned within the periphery of the coaxial cable's oblique terminal section, reducing stray electromagnetic fields and capacitive coupling, and featuring conductive vias for enhanced current carrying capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the conductor length is increased to improve current carrying capacity, then the current carrying capacity is improved, but electromagnetic radiation and cross-talk increase
Solution Approach 1:
The contact tips are positioned within the periphery of the coaxial cable's oblique terminal section, nesting the signal transmission path inside the shielded cable structure. This allows the conductors to be as long as needed for current carrying while the coaxial cable's outer conductor shields the electromagnetic radiation, resolving the contradiction between length and radiation.
Solution Approach 2:
The coaxial cable's outer conductor acts as an intermediary shield between the inner conductor carrying the signal and the external environment. This intermediate shielding layer allows long conductors to carry current without radiating electromagnetic energy outward, enabling both long conductor length and low radiation simultaneously.
2Object-generated harmful factors
If the conductor length is minimized to reduce electromagnetic radiation, then electromagnetic radiation is reduced, but the usable frequency range is limited
Solution Approach 1:
By nesting the contact tips within the coaxial cable structure, the effective radiating length is minimized to only the exposed tip portion, while the full length of the inner conductor can be used for signal transmission. The outer conductor continuously shields along the entire length, allowing frequency extension without increasing radiation.
Solution Approach 2:
The coaxial cable structure provides continuous electromagnetic shielding as an intermediary, allowing the signal to travel through long conductors at high frequencies without the conductors acting as antennas. This enables extended frequency range while maintaining low radiation levels.
3Measurement precision
If needle-like probe tips are used for precise measurement, then measurement precision is improved, but inductive losses increase at high frequencies
Solution Approach 1:
The coaxial cable's outer conductor serves as an intermediary that provides a return path for the signal current close to the inner conductor. This configuration creates a controlled impedance transmission line that minimizes inductive effects and reduces energy losses, while still allowing needle-like tips for precise pad contact.
Solution Approach 2:
The patent changes the electrical parameters by using a coaxial cable with specific characteristic impedance (typically 50 ohms) and controlled dimensions. This parameter optimization ensures minimal inductive reactance and maximum signal transmission efficiency at high frequencies, while maintaining the needle tip geometry for precise measurement.
4Ease of operation
If signal traces are extended to reach contact tips, then connectivity is improved, but signal reflection and inductive losses increase
Solution Approach 1:
The coaxial cable structure acts as an intermediary transmission medium that maintains controlled impedance throughout the extended signal path. The outer conductor provides a consistent reference plane and return path, preventing impedance discontinuities that cause signal reflection, while allowing long trace extensions to reach distant contact tips.
Solution Approach 2:
By controlling the dimensions and materials of the coaxial cable (conductor diameters, dielectric properties, spacing), the characteristic impedance is maintained constant along the entire signal path. This parameter control prevents impedance mismatches and signal reflection, enabling long extended traces without degrading signal quality.
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 effectively reduces cross-talk and extends the usable frequency range by minimizing electromagnetic radiation and increasing current carrying capacity, providing improved performance at higher frequencies with reduced crosstalk and enhanced shielding.
Implementation Method 1
integrated shielding, where contact tips are positioned within the periphery of the coaxial cable's oblique terminal section, reducing stray electromagnetic fields
Implementation Method 2
featuring conductive vias for enhanced current carrying capacity
Data Source
AI summary
A high frequency probe has contact tips located within the periphery of a terminal section of a coaxial cable and shielded by a ground conductor of the coaxial cable.