Moisture-Detecting RFID Tag With Relay Antenna
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Solution Overview
Problem
Existing sanitary articles with moisture-detecting RFID tags face challenges in achieving highly sensitive moisture detection due to variable RFID tag placement and positional relationships with readers, leading to inconsistent detection performance.
Innovation Solution
Incorporating a moisture-absorptive material adjacent to a moisture-detecting RFID tag with an elongated relay antenna that extends the communication range by relaying the tag's output, using an RFIC element and antenna element connected to the tag, and employing capacitive coupling between the relay antenna and the tag to vary signal intensity based on moisture levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an RFID tag is inserted into a diaper for moisture detection, then moisture detection function is provided, but detection sensitivity is insufficient due to variable tag placement and positional relationship with reader
Solution Approach 1:
The patent introduces a relay antenna that extends the communication range in a spatial dimension, allowing the reader to be positioned away from the sensitive crotch area while maintaining detection capability. The relay antenna acts as an intermediate transmission node that bridges the gap between the RFID tag in the diaper and the external reader, solving the positioning problem by adding a dimensional extension to the communication path.
Solution Approach 2:
The relay antenna serves as an intermediary element between the RFID tag and the reader. It receives signals from the RFID tag and retransmits them to the reader, enabling communication without requiring direct line-of-sight or close proximity between the tag and reader. This mediator approach allows flexible positioning and maintains detection sensitivity regardless of the reader's distance from the diaper.
2Ease of operation
If a relay antenna is added to extend communication range, then reader can be positioned away from sensitive areas improving user comfort, but device complexity increases
Solution Approach 1:
The relay antenna is designed with multi-functionality to justify its addition. It not only extends communication range but also provides signal amplification, impedance matching, and directional beamforming capabilities. The relay antenna can serve multiple purposes: extending range, improving signal quality, enabling flexible positioning, and even providing some degree of moisture detection redundancy, thereby reducing the overall system complexity despite adding a component.
Solution Approach 2:
The patent utilizes parameter changes in the relay antenna design, such as adjustable gain, variable beam direction, and tunable frequency response, to optimize system performance. By dynamically adjusting these parameters, the relay antenna can adapt to different usage scenarios, reducing the need for multiple fixed-function components and thereby managing device complexity while maintaining ease of operation.
3Measurement precision
If moisture-absorptive material is placed adjacent to RFID tag, then moisture detection accuracy is improved, but detection response time increases
Solution Approach 1:
The patent applies local quality by positioning the moisture-absorptive material in specific locations adjacent to the RFID tag where moisture is most likely to be detected. The material is strategically placed to maximize contact with potential moisture sources while maintaining a configuration that minimizes absorption time. This localized optimization ensures high detection accuracy without significant delay, as the material is positioned exactly where it is needed rather than distributed throughout the entire diaper.
Solution Approach 2:
The moisture-absorptive material is pre-positioned and pre-configured adjacent to the RFID tag during diaper assembly, ready to immediately interact with moisture upon contact. This preliminary arrangement eliminates any delay associated with material deployment or activation, allowing the system to transition directly from dry to detection mode, thereby minimizing response time while maintaining high 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
This configuration enables highly sensitive moisture detection across an extended communication range, allowing for reliable detection without direct reader application to sensitive areas, thus improving user comfort and detection accuracy.
Implementation Method 1
a moisture-absorptive material; a moisture-detecting RFID tag adjacent to the moisture-absorptive material
Implementation Method 2
the moisture-detecting RFID tag is configured to output a variation of a communication distance or a signal intensity, originated from a variation of a moisture amount included in the moisture-absorptive material
Implementation Method 3
employing capacitive coupling between the relay antenna and the tag to vary signal intensity based on moisture levels
Data Source
AI summary
A sanitary article is equipped with a moisture-detecting RFID tag that includes a moisture-absorptive material; a moisture-detecting RFID tag adjacent to the moisture-absorptive material; and a relay antenna that is connected to the moisture-detecting RFID tag and that extends the communication range by relaying an output of the moisture-detecting RFID tag. Moreover, the moisture-detecting RFID tag includes an RFIC element, and an antenna element that is connected to the RFIC element. The moisture-detecting RFID tag outputs a variation of a communication distance or a signal intensity, originated from a variation of a moisture amount included in the moisture-absorptive material.