Stackable RFID Tag with Coupling Device for Extended Range
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Solution Overview
Problem
Existing RFID tags face challenges in maintaining reliable operation when stacked or placed in close proximity due to parasitic coupling and limited range, making them unsuitable for bulk identification and display applications, especially in jewelry where space and orientation constraints are significant.
Innovation Solution
An improved RFID tag that operates in two modes: a short-range mode for bulk processing and a long-range mode when enhanced by a Coupling Device, such as a ferrite rod or tuned circuit, to extend the interrogation range and improve coupling with the interrogator antenna, even when tags are stacked or poorly oriented.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If RFID tags are made small for jewelry labels, then they can be stacked and stored efficiently, but their interrogation range becomes limited and unreliable
Solution Approach 1:
The system divides the RFID functionality into two segments: a small stackable tag for bulk handling and a separate coupling device (ferrite rod or tuned circuit) for range extension. The tag itself remains small and stackable, while the coupling device is activated only when the tag needs long-range interrogation during individual display.
Solution Approach 2:
The RFID system dynamically switches between two operational modes: short-range mode when tags are stacked in bulk, and long-range mode when a coupling device is introduced during individual display. This dynamic adaptation allows the same small tag to serve both bulk processing and individual interrogation needs.
2Quantity of substance
If RFID tags are placed in bulk or stacked for storage, then storage efficiency improves, but parasitic coupling between tags increases causing identification failures
Solution Approach 1:
The coupling device acts as an intermediary between the interrogator antenna and the RFID tag during individual display. It concentrates the electromagnetic field and directs it to the tag, enabling reliable long-range communication without interference from other stacked tags.
3Ease of operation
If RFID tags are placed in display pockets away from the interrogator antenna, then aesthetic display is improved, but coupling with the antenna deteriorates
Solution Approach 1:
The coupling device (ferrite rod or tuned circuit) serves as a field conduit that bridges the gap between the interrogator antenna and the tag positioned in the display pocket. It concentrates and directs the electromagnetic field to the tag's location, enabling reliable communication despite the tag's distance from the antenna.
Solution Approach 2:
The coupling device creates a localized concentration of electromagnetic field energy at the tag's position within the display pocket. This local field enhancement ensures reliable coupling without requiring the tag to be positioned close to the main interrogator antenna, preserving display aesthetics.
4Length of stationary object
If ferrite rods or tuned circuits are added to extend tag range, then interrogation range increases, but device complexity increases
Solution Approach 1:
The system dynamically activates the coupling device only when long-range interrogation is needed during individual display. During bulk stacking and storage, the simple stackable tag operates without the coupling device, maintaining simplicity. The coupling device becomes part of the system only when needed.
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 RFID tag can efficiently identify items both when stacked in bulk and when individually displayed, offering enhanced range and reliability by converting from a short-range to a long-range mode with the aid of a Coupling Device, addressing the limitations of existing tags in jewelry applications.
Implementation Method 1
The at least one second part is a coupling device adapted to enhance the coupling between the at least one RFID tag and an associated interrogator antenna
Implementation Method 2
The coupling device includes a tuned circuit adapted to amplify the local field near the RFID tag
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The problem to solve is how to extend the operating range of small stackable RFID tags when they are placed in an undesirable orientation. Disclosed is an RFID tag that operates in two modes whereby in a first mode the tag has a short range and in a second mode the tag has a long range. The tag is converted from the first mode short range device into the second mode long range device by placing it close to a coupling device. That is in the second mode the tag becomes a two part RFID tag system (1400) capable of communicating with an interrogator antenna (1407).