Watch Antenna Assembly Using Elastomeric PCB Interconnects
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Solution Overview
Problem
Implementing RF antennas in metallic-housed mobile devices, such as wristwatches, is challenging due to the Faraday cage effect, complex PCB interconnections, and impedance issues, which are difficult to maintain in mass production.
Innovation Solution
An antenna assembly using an elastomeric connector with conductive filaments and insulating filaments extending between the antenna structure and the PCB, providing a redundant, elastic, and precise electrical connection, compensating for geometric tolerances and assembly mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna is connected to the PCB using traditional rigid interconnection methods, then the electrical connection is stable, but the assembly process becomes complex and sensitive, making it difficult to maintain consistent quality in mass production
Solution Approach 1:
The patent employs an elastomeric connector with conductive filaments embedded in an elastomeric matrix to connect the antenna structure to the PCB. This flexible connector accommodates assembly tolerances and geometric mismatches while maintaining reliable electrical connection, thereby simplifying the manufacturing process and enabling consistent quality in mass production without compromising connection stability
Solution Approach 2:
The elastomeric connector allows for parameter changes in terms of flexibility and elasticity, enabling the connection to adapt to varying assembly conditions. The elastomeric material's inherent compliance permits tolerance compensation, making the assembly process less sensitive to dimensional variations and reducing assembly complexity while maintaining connection reliability
2Device complexity
If the antenna is placed on a cover glass, then the antenna structure is simplified, but the electrical connection between the antenna and PCB deteriorates due to high frequency behavior issues
Solution Approach 1:
The elastomeric connector acts as an intermediary between the antenna structure on the cover glass and the PCB. This intermediate component provides a controlled electrical connection that maintains signal integrity at high frequencies, preventing the deterioration of signal receiving capability while allowing the antenna structure to remain simplified on the cover glass surface
3Strength
If the housing is made of metal, then the device has improved strength and appearance, but the housing acts as a Faraday cage, impairing antenna performance
Solution Approach 1:
The patent extracts the antenna structure from the metallic housing environment by placing it on the cover glass surface, thereby removing it from the Faraday cage effect of the metal housing. This separation allows the antenna to function independently outside the metallic enclosure, maintaining signal reception reliability while preserving the strength and appearance benefits of the metal housing
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
Facilitates a reliable, durable, and cost-effective interconnection between the antenna and PCB, ensuring consistent signal reception and ease of assembly, even in harsh environments.
Implementation Method 1
at least one elastomeric connector comprising a plurality of conductive filaments and insulating filaments extending between the antenna structure and the PCB
Implementation Method 2
elastomeric connector comprises numerous regularly arranged conductive filaments embedded in an insulating elastomeric material
Data Source
Figure 1~3
Figure 4~6
AI summary
The present invention relates to An antenna assembly for a mobile device comprising a printed circuit board (14) and an antenna structure (12; 42; 44) located at a distance from the printed circuit board (14), wherein the antenna structure (12; 42; 44) is electrically connected to the printed circuit board (14) via at least one elastomeric connector (20) comprising a plurality of conductive filaments (24) and insulating structure extending between the antenna structure (12, 42; 44) and the printed circuit board (14).