RFID Watch Crystal Antenna Resonator Design
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Solution Overview
Problem
Existing RFID-based watch transponders face challenges in increasing reading distance due to interference from metal watch components, leading to reduced functionality and higher costs, particularly in luxury watches with metal cases, where bulky external antennas compromise aesthetics, design, and integration.
Innovation Solution
A microtransponder with an integrated circuit chip electromagnetically coupled to a larger resonator antenna, made of transparent conductive materials, is integrated into the watch crystal, allowing for increased reading distance without bulk or obtrusive design, enabling non-invasive and cost-effective integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a large antenna is used to increase reading distance, then the reading distance is improved, but the watch becomes bulky and aesthetically compromised
Solution Approach 1:
The patent embeds the microtransponder antenna within the watch crystal structure, nesting the RFID functionality inside the existing watch architecture. The antenna is integrated into the crystal thickness rather than extending outward, allowing the watch to maintain its compact form while achieving extended reading distance through the resonator effect of the crystal itself.
Solution Approach 2:
The patent utilizes the thickness dimension of the watch crystal as the antenna structure, transforming a two-dimensional surface problem into a three-dimensional volume solution. By making the crystal itself resonant at RFID frequencies through its thickness, the system achieves extended reading distance without increasing the watch's lateral dimensions.
2Strength
If metal components are used in the watch, then the aesthetic and mechanical quality is improved, but the radio wave transmission is interfered with
Solution Approach 1:
The patent introduces a non-conductive adhesive layer between the metal case components and the crystal antenna, acting as an electromagnetic intermediary that blocks signal interference from the metal while allowing mechanical assembly. This thin adhesive layer prevents eddy currents and signal reflection from the metal surfaces, improving RFID readability without compromising the metal construction.
3Length of stationary object
If external reading devices are used, then the reading distance is extended, but the cost and complexity increases
Solution Approach 1:
The patent makes the watch crystal itself serve as the antenna and resonator, eliminating the need for separate external reading devices. The crystal's physical dimensions are engineered to resonate at RFID frequencies, allowing it to function as both the structural component and the electromagnetic antenna, thereby extending reading distance while reducing system complexity and cost.
4Adaptability or versatility
If the transponder is integrated into the watch, then the functionality is improved, but the reading distance is reduced due to interference
Solution Approach 1:
The patent changes the electromagnetic parameters of the watch crystal by adjusting its thickness and material composition to resonate at RFID frequencies. By tuning the crystal's physical parameters, it transforms from a passive structural component into an active electromagnetic resonator that extends reading distance while maintaining the integrated transponder functionality within the watch structure.
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 extends the reading distance of the microtransponder, facilitating access to advanced RFID services while maintaining the watch's mechanical and aesthetic integrity, and reducing production costs, allowing for flexible integration and easy upgrade options.
Implementation Method 1
a microtransponder (1) consisting of an antenna (1.2) and an integrated circuit chip (1.1) at least and which is associated, without electrical connection, by electromagnetic coupling, to a passive antenna of larger dimensions, called antenna-resonator (2)
Implementation Method 2
a passive antenna of larger dimensions, called antenna-resonator (2), making it possible, with less bulk and at lower cost, to increase the reading distance of said microtransponder (1)
Data Source
Figure 1~3.1
AI summary
The wristwatch (4) has a micro-transponder (1) e.g. ROM memory chip, including an antenna i.e. coil-on-chip type antenna, integrated to an integrated circuit chip. The micro-transponder is connected to a passive antenna i.e. antenna-resonator (2), of large dimensions without electrical connections, by using a magnetic/electromagnetic coupling. The antenna-resonator is situated near the micro-transponder and formed by printing an ink formed of transparent electrically conducting polymer compound, on an inner surface of a watch glass (3) i.e. support.