Non-contact Antenna with Segmented Coils for Metal Casing Interference
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Solution Overview
Problem
Non-contact communication devices face challenges in maintaining consistent communication performance due to varying antenna shapes and sizes in reader/writer modules, especially when installed in devices with metal casings, which can lead to communication deterioration and radiation noise interference.
Innovation Solution
A non-contact communication device with an antenna configuration that includes a standard coil and smaller coils connected in series or parallel, where the smaller coils are positioned to overlap the winding part of the reader/writer antenna, ensuring optimal alignment and reducing interference from metal casings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil antenna is used in non-contact communication devices, then the device structure is simple, but communication performance deteriorates when installed in devices with metal casings and positional offsets occur
Solution Approach 1:
The antenna is divided into multiple coils with different aperture sizes (first coil, second coil, third coil, fourth coil) arranged in a specific pattern. This segmentation allows each coil to contribute differently to the overall magnetic field, improving communication reliability when installed in devices with metal casings and reducing the impact of positional offsets.
Solution Approach 2:
Different coils are designed with different aperture sizes to create localized magnetic field characteristics. The smaller aperture coils provide focused magnetic flux in specific regions, while larger aperture coils provide broader coverage. This local quality differentiation ensures stable communication performance across various installation positions and metal casing configurations.
2Length of moving object
If antenna coils are closely coupled to maximize coupling coefficient, then communication distance is extended, but radiation noise increases and communication dead zones are created
Solution Approach 1:
The antenna system uses multiple coils with different aperture sizes arranged in a specific pattern rather than a single large coil. This segmentation distributes the magnetic flux generation across multiple sources, extending communication distance while reducing peak radiation noise levels and preventing communication dead zones that would occur with closely coupled single coils.
Solution Approach 2:
The antenna employs asymmetric coil aperture sizes (first coil and second coil with different apertures, third coil and fourth coil with different apertures) to create an optimized magnetic field distribution. This asymmetry allows the system to extend communication distance while controlling radiation noise characteristics and eliminating dead zones.
3Length of moving object
If the antenna aperture size is increased to improve communication distance, then tolerance against positional offsets is reduced
Solution Approach 1:
The antenna system segments the aperture into multiple coils of different sizes. This segmentation creates a composite magnetic field that maintains communication distance through the combined effect of all coils while the smaller aperture coils provide tolerance against positional offsets by maintaining focused magnetic flux in critical regions.
Solution Approach 2:
Different coils with different aperture sizes provide localized magnetic field characteristics. The smaller aperture coils maintain focused magnetic flux for positional tolerance, while larger aperture coils extend overall communication distance. This local quality differentiation resolves the contradiction between communication distance and positional alignment tolerance.
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 enhances communication performance by maintaining communication distance and improving tolerance against radiation noise and positional offsets, preventing communication dead zones.
Implementation Method 1
If the IC card approaches the R/W and the like serving as the initiator, current flows through the coil serving as the antenna of the IC card due to electromagnetic induction by the RF signal output from the R/W
Implementation Method 2
by the capacitor connected to the coil serving as the antenna, a resonance frequency of a resonance circuit including the capacitor and the coil is adjusted
Data Source
AI summary
Provided is a non-contact communication device including an antenna configured to transmit data through non-contact communication after load-modulation of an RF signal from a reader/writer (R/W), wherein the antenna includes: a standard coil having an aperture with a predetermined size; and a small coil having an aperture with a size smaller than a size of the standard coil, wherein the standard coil and the small coil are connected in series or in parallel, and the small coil is arranged such that the aperture of the small coil overlaps a winding part of a coil that is an antenna of the R/W when the non-contact communication device is caused to face the R/W by matching a predetermined position of the non-contact communication device with a reference position of the R/W determined in advance as a position with which the predetermined position of the non-contact communication device is to be matched.