Self-Aligning EMF Sensor Structure to Prevent Air Gaps
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Solution Overview
Problem
Conventional electromagnetic field (EMF) sensors require precise assembly and maintenance to prevent misalignment between the center conductor and the insulator layer, which can lead to changes in coupling coefficient and characteristic impedance, resulting in inaccurate readings and potential electrical arcing due to air gaps.
Innovation Solution
The design incorporates a housing with multiple sections and a central conductor featuring frustrum shapes that self-align and maintain contact with dielectric elements, ensuring a tight fit and stability under axial and radial forces, thereby preventing misalignment and air gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cylindrical insulator layers are used with center conductors, then assembly is simpler, but misalignment and air gaps occur under thermal and mechanical stress, degrading sensor accuracy
Solution Approach 1:
The patent applies asymmetry by changing the conductor and insulator cross-section from circular to polygonal shapes (e.g., triangular, rectangular). This asymmetric geometry creates interlocking features that prevent relative rotation and misalignment between components, ensuring consistent coupling coefficient and characteristic impedance under thermal and mechanical stress without requiring complex alignment procedures
Solution Approach 2:
The patent employs curved or angled contact surfaces between the conductor and insulator, replacing flat cylindrical interfaces. The frustum-shaped conductor with angled sides creates tapered contact surfaces that maintain continuous dielectric contact under axial and radial forces, preventing air gap formation while distributing mechanical stress evenly
2Manufacturing precision
If precise assembly procedures are implemented, then initial alignment is improved, but maintenance requirements increase and assembly time is extended
Solution Approach 1:
The patent implements self-service through self-aligning geometric features where the polygonal conductor and insulator automatically orient themselves correctly during assembly. The interlocking asymmetric shapes guide proper positioning without requiring external alignment tools or procedures, enabling workers to achieve precise alignment through simple insertion while reducing maintenance needs
Solution Approach 2:
The patent applies preliminary action by pre-forming the asymmetric geometric features during manufacturing. The angular and tapered surfaces are created in advance, so that during assembly the components naturally settle into their correct positions without requiring post-assembly adjustment or calibration procedures
3Ease of manufacture
If air gaps are allowed between conductor and insulator, then assembly tolerance is relaxed, but electrical arcing and sensor damage occur under stress
Solution Approach 1:
The patent changes the geometric parameters of the conductor and insulator from cylindrical to polygonal shapes with angled surfaces. This parameter change creates overlapping contact zones that eliminate air gaps while maintaining relaxed assembly tolerances, as the angular geometry ensures continuous dielectric contact between the conductor and insulator even under thermal expansion and mechanical vibration
Solution Approach 2:
The patent applies beforehand cushioning by designing the frustum-shaped conductor with tapered sides that create gradual contact transitions. This geometric cushioning distributes mechanical and thermal stresses evenly across the interface, preventing sudden shifts that could create air gaps and subsequent electrical arcing
Data Source
AI summary
An electromagnetic field sensor may include a housing including an opening extending therethrough; a dielectric element including a first section having a first interior space and a second section having a second interior space, the dielectric element being received within the opening of the housing; and a conductor disposed within and approximating the first interior space and the second interior space of the dielectric element, the conductor including a first portion defining a first frustrum shape and a second portion defining a second frustrum shape, the first interior space receiving the first portion of the conductor and the second interior space receiving the second portion of the conductor. The electromagnetic field sensor for use in a matching network of a plasma generation system or other application.