Antenna Sub-Core Segmentation and Soft Potting for Shock Resistance

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Solution Overview

Problem

Existing vehicle antennas face challenges with stability and breakage due to increasing bandwidth and core length, as well as susceptibility to shocks and temperature fluctuations, while softer casting compounds improve shock absorption but compromise magnetic properties.

Innovation Solution

The use of a soft potting compound with a Shore hardness of less than 40 A, combined with a plurality of sub-cores and a gap between them, enhances fracture resistance and electrical stability by allowing for relative motion and heat dissipation, while maintaining robustness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the core length is increased to expand bandwidth and transmission range, then the antenna performance is improved, but the susceptibility to breakage increases

Engineering Contradiction:
Improveantenna bandwidth and transmission rangeVSAvoidcore breakage susceptibility
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The core is divided into multiple sub-cores (at least two) arranged in series within the housing. This segmentation allows the antenna to achieve the required magnetic path length for expanded bandwidth and transmission range while each individual sub-core remains short and less susceptible to breakage. The sub-cores are positioned end-to-end to provide the cumulative magnetic effect of a long core without the fragility.

Inventive Principle:
Principle #1Segmentation

2Strength

If a softer potting compound is used to dampen shocks and reduce breakage risk, then the fracture resistance is improved, but the positioning precision of antenna components deteriorates

Engineering Contradiction:
Improvefracture resistanceVSAvoidcomponent positioning tolerance
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The housing is designed with pre-positioning features such as recesses, ledges, or geometric constraints that establish the correct component positions before the potting compound is applied. The softer potting compound (Shore A 10-30) then serves as a cushioning medium that absorbs shocks and vibrations while maintaining these pre-established positions. The positioning geometry is built into the housing structure itself, so the soft compound provides shock protection without compromising positioning precision.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If harder potting compound is used to maintain positioning precision, then the manufacturing precision is improved, but the shock damping capability deteriorates

Engineering Contradiction:
Improvecomponent positioning toleranceVSAvoidshock susceptibility
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The housing incorporates geometric positioning features (recesses, ledges, interference fits) that establish accurate component positions before potting. This allows the use of softer potting compounds (Shore A 10-30) that provide superior shock damping while the pre-built geometric constraints maintain the required positioning precision. The soft compound acts as a shock-absorbing matrix that fills gaps and dampens vibrations without relying on high hardness for positioning.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If multiple sub-cores are used to simplify production and reduce breakage, then the ease of manufacture and fracture resistance are improved, but the stability of antenna characteristics under shocks and temperature fluctuations deteriorates

Engineering Contradiction:
Improvecore production simplicityVSAvoidantenna characteristic stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Multiple separate sub-cores are combined within a single housing that provides a unified magnetic circuit path. The housing acts as a magnetic yoke that connects the sub-cores and maintains their relative positions. This merging approach allows each sub-core to be manufactured separately (improving ease of manufacture and reducing individual breakage risk) while the integrated housing ensures stable magnetic flux paths and consistent antenna characteristics under environmental stresses.

Inventive Principle:
Principle #5Merging (Combining)

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

This configuration results in a robust antenna with stable electrical properties, improved fracture resistance, and reduced susceptibility to shocks and temperature variations, ensuring long-term stability and performance.

Implementation Method 1

the potting compound with a Shore hardness of less than 40 A, combined with a plurality of sub-cores and a gap between them, enhances fracture resistance and electrical stability by allowing for relative motion and heat dissipation

Methodology Applied
Scientific EffectShock damping: Damping

Implementation Method 2

The soft potting compound allows the sub-cores a certain degree of movement when receiving an impact. If the sub-cores touch, an impact is transferred from the first sub-core to the second, potentially increasing the likelihood of breakage despite the soft potting compound

Methodology Applied
Scientific EffectHeat dissipation: Conduction (thermal)

Data Source

PatentEP3723196B1Antenna
Publication Date: 2023.07.12 SCHAFFNER EMV AG
  • EP3723196B1 patent drawingFigure 1~3
  • EP3723196B1 patent drawingFigure 4~5
  • EP3723196B1 patent drawingFigure 5~7

AI summary

Antenna comprising a housing (3), a core (1) and a coil (2) wound around the core (1), wherein the core (1) with the coil (2) is embedded in a potting compound (5) in the housing (3), wherein the potting compound (5) is softer than 40 Shore A.