RFID Tag Validation Using Waveguide Isolation and Segmented Readers
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Solution Overview
Problem
Current systems fail to guarantee 100% readability of ultra high frequency (UHF) RFID tags mounted in close proximity on a continuous web, especially those with long read ranges, at normal production speeds, due to difficulties in discriminating between adjacent tags and ensuring all tags are functional.
Innovation Solution
A radio frequency identification tag reading/writing station employing waveguide to coax adapters, window assemblies, and directional couplers to isolate and verify individual tags, using reflective or through techniques, while shielding adjacent tags from RF energy, and utilizing processors to compare tag designations for functionality evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If traditional reader/verification equipment is used to read RFID tags with long read ranges, then the tags can be read from a distance, but the system cannot effectively discriminate between adjacent tags spaced closely together
Solution Approach 1:
The patent divides the verification process into two distinct stages: first, a narrow angle reader verifies individual tags one at a time with high precision; second, a wide angle reader verifies multiple tags simultaneously from a distance. This segmentation allows the system to achieve both high discrimination accuracy for closely spaced tags and long read range verification.
Solution Approach 2:
The patent employs two readers with different angular characteristics - a narrow angle reader for localized precise verification of individual tags, and a wide angle reader for broader coverage verification. Each reader is optimized for its specific function, with the narrow angle reader providing high spatial resolution for closely spaced tags and the wide angle reader providing extended verification range.
2Productivity
If RFID tags are mounted in close proximity on a continuous web at high production speeds, then productivity increases, but the ability to ensure 100% readability of all tags is compromised
Solution Approach 1:
The patent performs preliminary verification of each RFID tag individually using the narrow angle reader before the tags are fully processed. This preliminary action ensures that defective tags are identified early, allowing for immediate correction or removal, thereby guaranteeing 100% readability of tags that proceed to final production.
Solution Approach 2:
The system incorporates real-time feedback from both narrow and wide angle readers to continuously monitor tag readability. The feedback mechanism allows the system to adjust and verify tag functionality dynamically during high-speed production, ensuring that only readable tags are approved for final use.
3Productivity
If reader equipment is designed to read tags at normal production speeds, then productivity is maintained, but the system cannot effectively verify all tags when they are spaced closely together
Solution Approach 1:
The verification process is segmented into two parallel verification channels: narrow angle verification for individual tags with high precision, and wide angle verification for multiple tags at speed. This segmentation allows the system to maintain high productivity while ensuring accurate verification of each tag through the narrow angle reader.
Solution Approach 2:
The patent merges the capabilities of two different reader types into a single integrated verification system. The narrow angle reader and wide angle reader work together, with the narrow angle reader providing precise individual verification and the wide angle reader providing rapid multi-tag verification, achieving both speed and accuracy.
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
Ensures nearly 100% readability and functionality of RFID tags in close proximity, even with long read ranges, at high speeds, by isolating individual tags and using advanced signal processing to validate each tag's functionality.
Implementation Method 1
a first waveguide to coax adaptor, a second waveguide to coax adapter, and a window assembly having a window therein, the window being sized and shaped such that a tag on the web of carrier material under test is exposed to radio frequency read/write energy
Implementation Method 2
such that tags on the web of carrier material adjacent to the tag under test are shielded from the radio frequency read/write energy
Implementation Method 3
a directional coupler, the directional coupler comprising a first port, a second port and a third port, with the radio frequency read/write energy passing through the directional coupler from the first port to the second port of the directional coupler, and with the signals emitted by the tag under test passing through the directional coupler from the second port to the third port of the directional coupler
Data Source
AI summary
A radio frequency identification tag reading/writing station is adapted to be used with a radio frequency identification tag reader/writer in order to read/write radio frequency identification tags on a continuous web of carrier material. The radio frequency identification tag reading/writing station includes a first waveguide to coax adaptor, a second waveguide to coax adapter, and a window assembly having a window therein, the window being sized and shaped such that a tag on the web of carrier material under test is exposed to radio frequency read/write energy, but such that tags on the web of carrier material adjacent to the tag under test are shielded from the radio frequency read/write energy. The first waveguide to coax adapter and the second waveguide to coax adapter are disposed end-to-end with the window assembly being disposed therebetween.