Low-Mass RFID Tag Antenna for Metal Detector Compatibility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
RFID devices often trigger false positives in metal detectors due to their metallic components, which can lead to manufacturing delays and the need for human intervention, thereby reducing the effectiveness of metal detection in food products.
Innovation Solution
The development of RFID devices with conductive structures that have a metal mass below the standard detection threshold of metal detectors, achieved by reducing the thickness of the conductive structure to a level below the skin depth and hollowing out areas with low current flow, allowing the RFID devices to function effectively without triggering false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RFID devices with standard conductive structures are used for tracking food products, then tracking performance is improved, but false positives in metal detectors increase
Solution Approach 1:
The patent changes the physical parameters of the conductive structure by reducing its thickness to below the skin depth (e.g., from typical thicknesses of micrometers to nanometer-scale thicknesses). This parameter change reduces the metal mass below the detection threshold of metal detectors while maintaining adequate RFID performance through compensation in other design aspects.
Solution Approach 2:
The patent applies local quality by making the conductive structure non-uniform in thickness, with varying thickness across different regions of the antenna. This allows optimization of RFID performance in critical areas while minimizing metal mass in less critical areas, achieving both tracking reliability and reduced false positives.
2Measurement precision
If the detection threshold of metal detectors is reduced to detect smaller metal objects, then detection sensitivity is improved, but false positives from RFID devices increase
Solution Approach 1:
The patent changes the mass parameter of the RFID device's conductive structure to be below the detection threshold of standard metal detectors. This allows metal detectors to maintain their standard detection thresholds and sensitivity settings without generating false positives from RFID tags.
3Object-generated harmful factors
If the metal mass of RFID devices is reduced below detection thresholds, then false positives are reduced, but RFID performance may deteriorate
Solution Approach 1:
The patent reduces the metal mass parameter while compensating for potential performance loss through other design modifications such as optimizing the conductive ink composition, adjusting antenna geometry, or using multiple thin layers instead of a single thick layer.
Solution Approach 2:
The patent employs composite materials by using conductive inks or composite conductive structures that combine metal particles with other materials. This allows achieving adequate electrical conductivity for RFID function with significantly reduced overall metal mass compared to traditional solid metal traces.
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
The modified RFID devices can be used throughout the entire manufacturing or production process without triggering false positives in metal detectors, maintaining adequate performance for tracking food products through the supply chain, and reducing the risk of sparking in microwaves.
Implementation Method 1
reducing the thickness of the conductive structure to a level below the skin depth
Data Source
AI summary
A conductive structure for use with a RFID device having a metallic mass that is below a standard detection threshold of a metal detector and a method of manufacturing the same is disclosed herein. The conductive structure preferably comprises a pair of dipole arms extending from a tuning loop, wherein each of the pair of dipole arms terminates in a load end. The conductive structure may be manufactured from a printed metallic ink, or by cutting, lasering, or etching a metal foil. The conductive structure is modified to reduce overall thickness and metallic mass of the device as much as possible, while still maintaining an acceptable level of performance. Portions of the load ends may also be hollowed out to further reduce the conductive structure's metallic mass.