Sensor Tag Resonator Frequency Correction via Stored Circuit Constants
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Solution Overview
Problem
Existing sensor tags using resonators for measuring physical quantities, such as temperature, face accuracy issues due to variations in resonator characteristics, leading to errors in measurement results.
Innovation Solution
A sensor tag configuration that includes a resonator generating a resonance signal, an antenna for radiating the signal, and a connection conductor, where the antenna and connection conductor are designed based on equivalent inductance or capacitance of the resonator, with an optional storage unit for equivalent circuit constant information, allowing for correction of resonant frequency variations and improved detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a resonator is used to sense physical quantities, then wireless measurement capability is achieved, but variations in resonator characteristics cause measurement errors
Solution Approach 1:
The patent applies feedback by measuring the resonant frequency and using it to calculate and transmit the physical quantity value through RFID communication. The measurement device receives the resonant frequency, calculates the physical quantity based on pre-stored relationships, and transmits the result back, creating a feedback loop that enables accurate measurement despite resonator variations
Solution Approach 2:
The patent utilizes parameter changes by exploiting the relationship between resonant frequency and physical quantities. The resonator's resonant frequency changes in response to physical quantity variations (such as temperature affecting crystal lattice), and this frequency parameter is measured and converted into quantitative physical quantity data through calibration curves or formulas
2Ease of operation
If resonant frequency is used for measurement, then wireless sensing is enabled, but resonator characteristic variations degrade detection accuracy
Solution Approach 1:
The patent introduces an intermediary - the RFID measurement device - that mediates between the resonator and the user. The resonator only needs to provide the resonant frequency signal, while the RFID device performs the complex tasks of frequency measurement, physical quantity calculation using pre-stored relationships, and wireless data transmission, thereby maintaining detection accuracy without compromising wireless operation
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 effectively suppresses the impact of resonator characteristic variations, enabling accurate measurement of physical quantities by correcting resonant frequency shifts, thereby enhancing detection accuracy.
Implementation Method 1
a resonator (111) that generates a resonance signal corresponding to a sensed physical quantity
Data Source
AI summary
A sensor tag (10) includes an antenna (102) and connection conductors (103) formed on a surface of a flexible substrate (101). A sensing element (110) is mounted on land conductors (131) of the connection conductors (103). The sensing element (110) is composed of a crystal vibrator (111) and an RFIC (112). The crystal vibrator (111) receives an excitation signal from the outside and generates a resonance signal of a resonant frequency corresponding to the sensed temperature. Equivalent circuit constant information including at least an equivalent inductance (Lxs) or an equivalent capacitance (Cxs) of the crystal vibrator (111) are stored in the RFIC (112).