RFID Module Capacitor Electrode Arrangement for Edge Reliability
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Solution Overview
Problem
Existing RFID devices for near-field communication face challenges in reducing size while maintaining efficient energy reception due to limitations in adjusting geometric parameters, particularly in handling thin substrates and minimizing antenna losses during manufacturing.
Innovation Solution
A module design featuring a planar capacitor with electrodes arranged on either side of the antenna turns, rather than inside them, which increases the distance between the antenna and the module edge, reducing the risk of sectioning and improving handling and robustness, and includes a method for forming electrodes before cutting to accommodate placement errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the antenna turns are peripherally positioned to increase effective area, then the antenna effective area is improved, but the distance between the antenna and module edge is reduced, increasing the risk of sectioning during manufacturing
Solution Approach 1:
The patent positions capacitor electrodes on both faces of the module, utilizing the third dimension (depth/thickness) to resolve the spatial conflict. By distributing electrodes across multiple faces and positioning them strategically, the design achieves sufficient effective area while maintaining safe distance from edges, preventing antenna sectioning during manufacturing.
Solution Approach 2:
The patent applies different electrode configurations to different faces of the module. The first face has electrodes positioned to maximize effective area, while the second face has electrodes positioned to provide structural support and maintain edge distance. This localized differentiation resolves the contradiction between area maximization and reliability.
2Volume of moving object
If thin substrates are used to reduce module size, then the module dimensions are improved, but the handling and manufacturing complexity increases
Solution Approach 1:
The patent employs a composite structure with capacitor electrodes on both faces of the thin substrate, creating a more rigid and handleable assembly. The dual-face electrode configuration provides structural reinforcement that compensates for the thinness of the substrate, improving ease of manufacture while maintaining compact dimensions.
Solution Approach 2:
The patent performs capacitor electrode formation on both faces before the final module assembly and cutting steps. This preliminary action ensures proper positioning and structural integrity are established early, facilitating easier handling during subsequent manufacturing processes despite using thin substrates.
3Quantity of substance
If capacitor electrodes are placed inside antenna turns to maximize capacitance density, then the capacitance value is improved, but the antenna robustness and handling are worsened
Solution Approach 1:
The patent distributes capacitor electrodes across both faces of the module rather than concentrating them in a single plane within the antenna turns. This three-dimensional distribution maintains sufficient capacitance density while improving antenna robustness by preventing electrode overlap and reducing handling complexity.
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 design enhances the robustness and handling of RFID modules, reduces manufacturing losses, and allows for a larger surface area for the antenna and capacitor within the same dimensions, improving energy reception and module integration in small form factors.
Implementation Method 1
the capacitance value of a planar capacitor with parallel plates or electrodes is equal to: C = (ε0 × εr × AC) / d in farad
Implementation Method 2
εr the relative permittivity of the material separating the two electrodes of the capacitor
Implementation Method 3
The energy received by means of this magnetic flux is then supplied to the microcircuit, with losses which correspond to the resistance of the winding forming the antenna
Implementation Method 4
The resonance frequency is chosen to match that of an external drive. The resonance frequency is calculated taking into account the electrical parameters of the device microcircuit
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Module comprising a base (20) supporting a planar capacitor, an antenna, and a microcircuit electrically connected therebetween to form a resonant electrical circuit, the capacitor including on a first side of the base a first electrode (30, 301, 302, 303), and a second electrode (300) that is placed on a second side opposite said first side and facing said first electrode, the second electrode and the first electrode having substantially the same shape. Each electrode has at least one first section and one second section that are placed on either side of the turns (40) of said antenna.