Capacitive Strap Coupling for Wearable Antenna Reliability
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Solution Overview
Problem
Existing radioelectric telecommunications devices face reliability issues due to the adjustable and mobile nature of the bracelet, which stresses the galvanic connection between the antenna and the electronic circuit, particularly in wearable devices like smartwatches and animal collars.
Innovation Solution
The implementation of an antenna loop with a conductive plate and a capacitive coupling mechanism using a conductive strap, eliminating the need for a galvanic connection and enhancing antenna performance through capacitive and inductive coupling, while providing a ground plane effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a galvanic connection is used between the antenna and the electronic circuit, then the antenna can be electrically connected to the circuit, but the reliability of the connection deteriorates due to stress from bracelet movement and adjustment
Solution Approach 1:
The patent replaces the mechanical galvanic connection system with an electromagnetic coupling system. The strap's conductive part forms a capacitive coupling with the conductive plate, creating an electrical connection through electric field interaction rather than direct physical contact. This substitution eliminates mechanical stress on the connection while maintaining electrical functionality.
Solution Approach 2:
The patent introduces an intermediary electromagnetic field between the antenna and the electronic circuit. The capacitive coupling acts as an intermediary mechanism that transfers electrical signals without requiring direct galvanic contact, thereby protecting the connection from mechanical stress while enabling signal transmission.
2Adaptability or versatility
If the bracelet is made adjustable and elastic to accommodate different wrist sizes, then the adaptability of the device is improved, but the stability of the galvanic connection deteriorates due to physical stress
Solution Approach 1:
The patent replaces the mechanical galvanic connection with an electromagnetic capacitive coupling system. This allows the bracelet to be adjustable and elastic for different wrist sizes while the electrical connection remains stable, as the capacitive coupling is not affected by mechanical stress from bracelet movement or adjustment.
3Device complexity
If a simple antenna structure is used, then the device complexity is reduced, but the connection reliability between antenna and circuit deteriorates
Solution Approach 1:
The patent maintains a simple antenna structure while improving connection reliability by substituting the mechanical galvanic connection with an electromagnetic capacitive coupling. The conductive plate and strap's conductive part form the coupling, eliminating the need for complex mechanical connection mechanisms while ensuring reliable electrical connection.
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 solution ensures reliable radioelectric communication by maintaining a stable connection despite movement and improves antenna performance, achieving efficient signal transmission and reception without reducing reliability.
Implementation Method 1
The conductive part of the strap extends parallel vis-à-vis the conductive plate and electrically insulated from said conductive plate, so that said conductive part is in capacitive coupling with said conductive plate
Implementation Method 2
There may also be an inductive coupling effect between the conductive part of the strap and the conductive plate, but typically the capacitive coupling will be preponderant
Data Source
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AI summary
Apparatus (100) comprising an antenna for sending and/or receiving radioelectric signals and a strap (104) serving to fasten the apparatus. The antenna comprises an antennal loop (200) and an antennal mass (302) bound together. The antennal loop includes a conducting plate (106) and a casing (108) containing an electronic circuit (400) and exhibiting at least one conducting face (202) which extends parallel opposite the conducting plate (106). The conducting plate (106) and the conducting face (202) of the casing are connected electrically (204) together on one side of the conducting face (202) of the casing and on the other side are connected electrically (110) with the electronic circuit (400). The antennal mass (302) comprises at least one conducting part (302) of the strap (104) in capacitive coupling with the conducting plate (106). Applications to connected watches and to geolocation collars for animals.