Electromagnetic Resonator Pressure Sensor for High Vacuum
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Solution Overview
Problem
Current pressure sensors for sub-atmospheric gas pressures suffer from low sensitivity and limited measurement ranges, with existing technologies failing to provide a simple and effective solution for high sensitivity and broad pressure measurement capabilities.
Innovation Solution
A pressure sensor utilizing a waveguide radiofrequency electromagnetic resonator with a dielectric material having a high coefficient of variation in permittivity with temperature, heated to vary its temperature and thus its permittivity, allowing for the determination of gas pressure through changes in resonance frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a Pirani type pressure sensor based on electrical conductor resistance variation is used, then the sensor structure is simple, but the sensitivity is low due to the small coefficient of resistance variation with temperature
Solution Approach 1:
The patent replaces the electrical resistance measurement system with an electromagnetic resonance frequency measurement system. Instead of measuring resistance changes in a heated conductor, the invention uses a heated dielectric resonator where the resonance frequency shifts with temperature, providing much higher sensitivity for pressure measurement.
Solution Approach 2:
The invention changes the measurement parameter from electrical resistance to electromagnetic resonance frequency. The resonance frequency of the dielectric resonator is highly sensitive to temperature changes, and since the resonator is heated by gas pressure, this provides indirect high-sensitivity pressure measurement through frequency shifts.
2Adaptability or versatility
If a mechanical resonance MEMS type pressure sensor is used, then the measurement range is extended, but the sensor cannot measure high vacuum levels below 10^-1 Pa
Solution Approach 1:
The patent replaces the mechanical resonance system with an electromagnetic resonance system. The electromagnetic resonator is not subject to the same mechanical limitations as MEMS devices, allowing it to operate reliably in high vacuum environments where mechanical sensors fail.
Solution Approach 2:
The invention utilizes the thermal equilibrium phase transition concept where the heated dielectric resonator reaches thermal equilibrium with the surrounding gas at different pressure levels. This thermal coupling mechanism works effectively across a broad pressure range including high vacuum, unlike mechanical resonance which requires specific pressure conditions.
3Measurement precision
If acoustic resonators are used for gas pressure measurement, then the measurement capability is provided, but the accuracy and measurement range are limited
Solution Approach 1:
The patent replaces acoustic resonance with electromagnetic resonance. The electromagnetic field interacts with the dielectric material of the resonator, and this interaction is strongly influenced by the thermal state of the resonator which is determined by gas pressure. This provides both high accuracy and broad measurement range.
Solution Approach 2:
The invention uses a composite structure combining a dielectric resonator material with specific thermal and electromagnetic properties. The dielectric material provides both the electromagnetic resonance function and the thermal coupling to the gas, creating a multi-functional system that achieves both accuracy and wide measurement range.
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 solution provides enhanced sensitivity and a broader measurement range, capable of accurately measuring pressures from less than 1 Pa to about 10^-3 Pa with reduced noise sensitivity, surpassing the limitations of existing technologies.
Implementation Method 1
a waveguide radiofrequency electromagnetic resonator with a dielectric material having a high coefficient of variation in permittivity with temperature
Implementation Method 2
The electrical conductor loses heat by conduction with the gas molecules in which it is immersed
Implementation Method 3
a device for heating said resonator
Implementation Method 4
an excitation circuit configured to propagate an electromagnetic field in said resonator; a device for detecting the electromagnetic resonance frequency of the resonator
Data Source
Figure 1~3
Figure 4~8
Figure 9~13
AI summary
The invention relates to a pressure sensor (1), comprising: -an electromagnetic resonator (3) with a waveguide comprising a dielectric material having a dielectric permittivity varying with temperature; -an excitation circuit (2) configured to propagate an electromagnetic field in said resonator; -a heating device for said resonator; -a device (4) for detecting the electromagnetic resonance frequency of the resonator; -a device (5) for determining the gas pressure surrounding the sensor as a function of the detected resonance frequency of the resonator.