Passive RFID Sensor With Variable Component For Pressure Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing measurement systems for variable parameters are often bulky, expensive, and require frequent power source changes, posing challenges in accessibility and safety, especially in small form factors like tire pressure monitoring, and traditional RFID systems lack precise frequency control.
Innovation Solution
A measurement sensor using a radio frequency identification (RFID) circuit with a variable component that changes its frequency in response to the measured parameter, allowing for real-time data transmission without a power source, utilizing components like capacitors or coils that vary with pressure or other environmental changes, and encoding data for security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional measurement systems are used, then measurement functionality is achieved, but the systems are bulky, expensive, and require frequent power source changes
Solution Approach 1:
The patent extracts and eliminates the power source (battery) from the measurement sensor, transforming it from an active to a passive device. The sensor is activated temporarily through electromagnetic induction from the reader, allowing measurement functionality without requiring a permanent power source, thereby improving reliability while reducing complexity.
Solution Approach 2:
The passive RFID sensor serves itself by harvesting energy from the reader's electromagnetic field during the interrogation process. The sensor uses this induced energy to power its measurement circuitry and transmit data back to the reader, eliminating the need for external power sources or recharging infrastructure.
2Volume of moving object
If small form factor sensors are used, then accessibility for power changes is improved, but power source changes become more difficult and expensive
Solution Approach 1:
By removing the power source entirely from the small sensor, the patent eliminates the maintenance burden of power source replacement. The passive sensor can be installed in hard-to-reach locations (such as inside tires) without concern for battery replacement, making the system both compact and maintenance-free.
3Use of energy by moving object
If batteries are used in small sensors, then power source is available, but disposal and safety issues arise
Solution Approach 1:
The patent removes the battery from the sensor system, completely eliminating battery-related environmental and safety concerns. The passive sensor design requires no disposable power sources, making it environmentally friendly and safe for long-term deployment in various applications including automotive and consumer products.
4Adaptability or versatility
If RFID tags operate at uncontrolled frequencies, then reader accommodation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent uses a variable capacitor whose capacitance changes in response to the measured parameter (e.g., pressure, temperature). This changes the resonant frequency of the RFID tag's LC circuit in a predictable manner. The reader detects these frequency shifts and converts them into measurement readings, achieving both adaptability and precision through controlled parameter changes.
Solution Approach 2:
The system establishes a feedback loop where the sensor's resonant frequency serves as the measurement signal. The reader continuously monitors the frequency of the backscattered signal from the passive sensor, and frequency deviations from the nominal value provide information about the measured parameter, enabling precise measurements through frequency-based feedback.
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
Enables a compact, cost-effective, and reliable system for measuring parameters like pressure or temperature, with secure data transmission, reducing the need for frequent power changes and improving system performance and accuracy.
Implementation Method 1
The tags contain no power source and rely upon 'activation' via electromagnetic induction from the reader in order to power the circuit contained within the tags.
Implementation Method 2
The pressure detection sensor includes a capacitor whose capacitance changes by a pressure change
Implementation Method 3
a frequency scanning means for detecting a resonance frequency decided by the antenna coil and the capacitor of the pressure detection sensor
Data Source
Figure 1~2
AI summary
The invention is directed to a measurement sensor comprising a radio frequency identification circuit for measuring a parameter. The circuit comprises at least one component in which a characteristic of that component can be changed to reflect a change in a measured parameter, such that the frequency of the sensor varies according to changes in the measured parameter. The invention extends to a system for measuring a variable parameter that incorporates such a sensor.