Passive RF Temperature Sensor Using Crystal Oscillator
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Solution Overview
Problem
Current temperature measurement methods, such as mercury thermometers, pose safety risks and environmental pollution, and quartz crystal oscillators require external power, making them inconvenient for use.
Innovation Solution
A wireless and passive temperature measurement system that uses a crystal oscillator circuit activated by energy feedback RF signals, allowing for remote temperature calculation without external power, replacing traditional mercury thermometers and improving user convenience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a quartz crystal oscillator is used to measure temperature, then measurement precision and speed are improved, but device complexity increases due to the need for external power supply
Solution Approach 1:
The temperature measurement device harvests energy from ambient RF signals to power its own crystal oscillator circuit, eliminating the need for external power supply or battery. The device autonomously converts received RF energy into electrical energy to drive the oscillator and perform temperature measurements, making the system self-powered and significantly reducing device complexity.
Solution Approach 2:
An energy harvesting circuit acts as an intermediary between ambient RF signals and the crystal oscillator circuit. This intermediary component converts RF energy into usable electrical energy, enabling the oscillator to operate without direct external power connection while maintaining measurement precision.
2Measurement precision
If a mercury thermometer is used for temperature measurement, then measurement precision is maintained, but safety and environmental harm worsen due to mercury toxicity and glass breakage risks
Solution Approach 1:
The patent replaces the mechanical mercury thermometer system with an electronic crystal oscillator-based temperature measurement system. This substitution eliminates mercury and glass components, removing the associated safety hazards and environmental pollution while maintaining medical-level temperature measurement precision through the oscillator's frequency-temperature relationship.
Solution Approach 2:
The invention changes the measurement parameter from mercury column height (mechanical) to crystal oscillator frequency (electrical). This parameter change enables wireless, non-contact temperature measurement without the safety risks of mercury exposure or glass breakage, while achieving superior measurement speed and precision.
3Measurement precision
If a mercury thermometer is used, then temperature measurement capability is maintained, but productivity decreases due to long measurement time and troublesome data reading
Solution Approach 1:
The patent replaces the slow mechanical reading process of mercury thermometers with rapid electronic frequency measurement of the crystal oscillator. The oscillator's frequency changes with temperature, and this frequency can be measured electronically and transmitted wirelessly, dramatically reducing measurement time and improving data reading efficiency.
Solution Approach 2:
The crystal oscillator provides periodic oscillations whose frequency is directly related to temperature. This periodic action enables continuous, rapid measurement cycles compared to the single-use nature of mercury thermometers, significantly improving productivity through fast, repeatable measurements.
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 system enables rapid and accurate temperature measurement with improved safety and reduced environmental impact, enhancing working efficiency in medical settings by eliminating the need for external power and hazardous materials.
Implementation Method 1
converting the energy feedback RF signal into electric energy
Implementation Method 2
the technology of quartz crystal oscillator can be used to measure temperature
Data Source
AI summary
The present disclosure provides a method and a system for wirelessly and passively measuring temperature and devices forming the system. The method includes: receiving an energy feedback radio frequency (RF) signal by a temperature measuring end; converting the energy feedback RF signal into electric energy and storing the electric energy; and starting the temperature measuring end after obtaining the electric energy, and transmitting a RF signal under the current temperature to a terminal, and calculating the current temperature through the terminal. The method, the system and the devices forming the system provided in the present disclosure are capable of activating the crystal oscillator or the ceramic oscillator wirelessly and passively, therefore, the method, the system and the devices can be used to wirelessly and passively measure temperature, which is convenient.