Removable Memory Card Antenna Shielding Design
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Solution Overview
Problem
Existing removable memory cards with integrated NFC antennas face challenges such as shielding issues, reduced universality due to varying slot designs in mobile communication devices, and instability in transmission characteristics, which hinder their use in cashless payment applications.
Innovation Solution
A removable memory card design featuring a ferrite-metal dual or triple layer on its outer edge, with the ferrite layer covered by a metal layer, strategically positioned to minimize shielding and enhance electromagnetic field transmission, allowing for stable operation across different device slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the antenna is located directly on the removable memory card body, then the structure is compact and easy to manufacture, but the transmission characteristics are unstable due to shielding by slot components
Solution Approach 1:
The patent introduces a non-conductive layer as an intermediary between the antenna and the slot components. This layer acts as a mediator that prevents direct contact and electromagnetic coupling between the antenna and the conductive slot structure, thereby stabilizing transmission characteristics while maintaining the compact integrated design.
Solution Approach 2:
The patent employs composite material structures combining conductive and non-conductive layers in a multi-layer configuration. This composite approach allows the antenna to maintain its electromagnetic functionality while the non-conductive layers provide shielding and isolation from the slot components, resolving the stability issue without compromising manufacturability.
2Reliability
If the antenna is placed as an external protruding part, then transmission features are improved, but the device becomes less universal due to varying slot recess depths
Solution Approach 1:
The patent applies local quality by positioning the non-conductive layer specifically at the antenna location on the card body, rather than making the entire card structure non-conductive or protruding. This localized approach provides the necessary electromagnetic isolation at the critical antenna area while maintaining the card's standard dimensions and compatibility with existing slot designs.
Solution Approach 2:
The patent transitions from a two-dimensional planar antenna design to a three-dimensional structure by adding the non-conductive layer in the vertical dimension. This dimensional change allows the antenna to achieve better electromagnetic characteristics without protruding from the card surface, thus maintaining universality across different device slots.
3Object-affected harmful factors
If the antenna is surrounded by conductive layers, then shielding is improved, but transmission characteristics deteriorate due to excessive shielding
Solution Approach 1:
The patent implements selective shielding by placing non-conductive layers only at specific locations around the antenna where shielding is needed, rather than completely enclosing the antenna in conductive material. This localized non-conductive shielding prevents harmful electromagnetic coupling with slot components while preserving the antenna's ability to transmit and receive signals effectively.
Solution Approach 2:
The patent uses composite material structures combining conductive and non-conductive layers in a balanced configuration. The conductive layers provide necessary electromagnetic shielding, while the non-conductive layers provide isolation and prevent excessive shielding effects, achieving an optimal balance between protection and transmission performance.
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 improves the antenna's transmitting and receiving features, ensuring stable communication channels and universal compatibility with various mobile device slots, while allowing for easy production and use in cashless payment systems.
Implementation Method 1
The dual layer consists of a ferrite layer that is covered by a metal layer from the outside. The triple layer consists of a ferrite layer that is in the middle and that is enclosed by metal layers.
Implementation Method 2
The solution describes a configuration that improves transmission characteristics of the antenna... a ferrite layer that is covered by a metal layer from the outside
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An antenna is located in the body of a removable memory card in such a way that at least one part of the antenna (2) is adjacent to that outer rim (10) of the card, which is near the entrance of the SD card slot after the card is inserted into the slot. The surface of the removable memory card (1) is covered with a ferrite layer (4) and a metal layer (4). The metal layer (4) screens the antenna (2) besides the uncovered zone (9), which is next to the outer rim (10) of the card. The uncovered zone (9) can be formed by a stripe with a width of up to 2 mm. The metal layer (4) can be made of copper or of aluminium and the ferrite layer (3) contains at least 50%, preferably however more that 60% of ferrite. The antenna (2) can be made of conductive loops basically of a rectangular shape, preferably in two separate parts on both sides of a PCB layer (5). The material of the card can contain a powder ferrite with at least 25% volume share. The powder ferrite can be made of ferrite particles having various chemical composition and various shape, preferably with a granularity from 20 μm to 70 μm.