RFID Conveyor Magnetic Loop Antenna for Detection Accuracy
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Solution Overview
Problem
Conveyor systems using standard UHF RFID technology face issues with large reading areas and radiation rebounds, leading to detection errors and the need for spacing objects, which hampers production flow, and existing solutions like tunnels or HF magnetic antennas are either inefficient or costly.
Innovation Solution
A conveyor system with a magnetic loop formed by the conveyor frame and adjacent roller shafts, excited by an excitation circuit, which includes a second magnetic loop or conductive strand, to create a localized magnetic field for efficient RFID tag reading, minimizing radiation leaks and object spacing requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If standard UHF RFID antennas are used, then the reading area is large, but radiation rebounds occur and detection errors increase
Solution Approach 1:
The patent changes the fundamental parameter of antenna operation from UHF (electromagnetic radiation) to HF magnetic field induction. This parameter change transforms the reading mechanism from wide-area radiation to localized magnetic coupling, eliminating radiation rebounds while maintaining reliable detection within the conveyor structure.
Solution Approach 2:
The conveyor frame and roller shafts serve as an intermediary magnetic circuit that guides and confines the magnetic field. This intermediary structure channels the magnetic flux between the excitation coil and RFID tags, preventing field leakage and rebounds while maintaining a controlled reading area.
2Area of stationary object
If tunnel structures are used to limit radiation spread, then reading area is controlled, but radiation leaks remain at entrance and exit
Solution Approach 1:
The patent extracts the radiation containment function from a separate tunnel structure and integrates it directly into the conveyor frame and rollers. The magnetic circuit is formed by the conveyor's own structural elements, eliminating the need for additional containment structures and their associated leakage points.
Solution Approach 2:
The patent merges the conveyor structural elements (frame and rollers) with the RFID antenna system. The frame and rollers become both the mechanical support and the magnetic circuit, combining structural and electromagnetic functions to eliminate separate containment structures.
3Reliability
If objects are spaced apart to avoid detection errors, then detection accuracy improves, but production flow is penalized
Solution Approach 1:
The patent converts the potential harm of magnetic field interference into a benefit by using the conveyor's metallic structure as a magnetic circuit. The structure that could potentially cause rebounds becomes the guiding pathway for magnetic flux, enabling continuous operation without spacing while maintaining accurate detection.
4Reliability
If HF magnetic antennas are used, then radiation rebounds are avoided, but system complexity and cost increase
Solution Approach 1:
The patent makes the conveyor system self-serving by using its own frame and rollers as the magnetic circuit components. The existing structural elements perform dual functions: mechanical support and electromagnetic flux guidance, eliminating the need for separate antenna structures and reducing overall system complexity.
Solution Approach 2:
The conveyor frame and rollers serve multiple functions simultaneously: they provide mechanical support for the conveyor, guide the magnetic flux, and form the magnetic circuit for RFID communication. This multi-functionality reduces the number of separate components needed and simplifies the overall system.
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 reduces radiation rebounds and maintains production flow by ensuring accurate object positioning with reduced spacing, while being cost-effective and adaptable for various RFID tag orientations and types.
Implementation Method 1
an RFID interrogator exciting a radiant antenna for reading information from said identification tag
Implementation Method 2
said excitation circuit comprises a second magnetic loop located under said first magnetic loop and magnetically coupled with it
Implementation Method 3
said excitation circuit comprises a conductive strand located under said first magnetic loop and magnetically coupled with it
Data Source
Figure 1~3
Figure 4~6
AI summary
A conveyor system for identifying an object (16) on which an identification tag (26) is affixed, comprising a conveyor frame (12) for supporting between its two opposite sides (12A, 12B) a plurality of transverse conveyor rollers (14) each having a roller shaft (14A) and an RFID interrogator exciting a radiant antenna for reading information from the identification tag, the radiant antenna being a first magnetic loop (22) formed by the conveyor frame and two adjacent roller shafts and excited by an excitation circuit (18) connected to, but distinct from, said RFID interrogator.