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A Wireless Passive LC Resonant Sensor Based on LTCC under High-Temperature/Pressure Environments.

Qin L, Shen D, Wei T, Tan Q, Luo T, Zhou Z, Xiong J - Sensors (Basel) (2015)

Bottom Line: Through the theoretical analysis of the sensor structure model, it is found that the increase in the dielectric constant and the decrease in the Young's modulus of DuPont 951 ceramic are the main causes that affect the pressure signal in high-temperature measurement.Through calculations, the Young's modulus of DuPont 951 ceramic is found to decrease rapidly from 120 GPa to 65 GPa within 400 °C.Finally, a temperature compensation structure is proposed and fabricated, and the pressure response after temperature compensation illustrates that temperature drift is significantly reduced compared with that without the temperature compensation structure, which verifies the feasibility the proposed temperature compensation structure.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Instrumentation Science & Dynamic Measurement, Ministry of Education, North University of China, Tai Yuan 030051, China. qinli@nuc.edu.cn.

ABSTRACT
In this work, a wireless passive LC resonant sensor based on DuPont 951 ceramic is proposed and tested in a developed high-temperature/pressure complex environment. The test results show that the measured resonant frequency varies approximately linearly with the applied pressure; simultaneously, high temperature causes pressure signal drift and changes the response sensitivity. Through the theoretical analysis of the sensor structure model, it is found that the increase in the dielectric constant and the decrease in the Young's modulus of DuPont 951 ceramic are the main causes that affect the pressure signal in high-temperature measurement. Through calculations, the Young's modulus of DuPont 951 ceramic is found to decrease rapidly from 120 GPa to 65 GPa within 400 °C. Therefore, the LC resonant pressure sensor needs a temperature compensation structure to eliminate the impact of temperature on pressure measurement. Finally, a temperature compensation structure is proposed and fabricated, and the pressure response after temperature compensation illustrates that temperature drift is significantly reduced compared with that without the temperature compensation structure, which verifies the feasibility the proposed temperature compensation structure.

No MeSH data available.


Equivalent measurement principle of the fabricated sensor.
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sensors-15-16729-f003: Equivalent measurement principle of the fabricated sensor.

Mentions: The sensor measurement principle is shown in Figure 3. The fabricated sensor can be simplified as a resistor-inductor-capacitor (R-L-C) series connection, where the resistance is caused by the coil wire. The inductor coil is coupled to the antenna coil, which sends out an alternating current sweep frequency signal of a certain bandwidth. When the frequency of the sweep signal approximates the sensor self-resonant frequency f0, the impedance information of the antenna, including the real part, imaginary part, amplitude, and phase, will mutate. By extracting the antenna impedance information, the sensor frequency can be obtained. Generally, we focus on the impedance phase part of the antenna; the mutated peak frequency fmin has the following relation with f0 [10]:(1)fmin=f0(1+ k24 + 18Q2)where k is the coupling coefficient between the antenna coil and the inductor coil, and Q denotes the sensor quality factor. Because the coupling between two coils is usually very weak, k is very small, while the quality factor Q is large. Thus, the difference between fmin and f0 can be neglected [11].


A Wireless Passive LC Resonant Sensor Based on LTCC under High-Temperature/Pressure Environments.

Qin L, Shen D, Wei T, Tan Q, Luo T, Zhou Z, Xiong J - Sensors (Basel) (2015)

Equivalent measurement principle of the fabricated sensor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541903&req=5

sensors-15-16729-f003: Equivalent measurement principle of the fabricated sensor.
Mentions: The sensor measurement principle is shown in Figure 3. The fabricated sensor can be simplified as a resistor-inductor-capacitor (R-L-C) series connection, where the resistance is caused by the coil wire. The inductor coil is coupled to the antenna coil, which sends out an alternating current sweep frequency signal of a certain bandwidth. When the frequency of the sweep signal approximates the sensor self-resonant frequency f0, the impedance information of the antenna, including the real part, imaginary part, amplitude, and phase, will mutate. By extracting the antenna impedance information, the sensor frequency can be obtained. Generally, we focus on the impedance phase part of the antenna; the mutated peak frequency fmin has the following relation with f0 [10]:(1)fmin=f0(1+ k24 + 18Q2)where k is the coupling coefficient between the antenna coil and the inductor coil, and Q denotes the sensor quality factor. Because the coupling between two coils is usually very weak, k is very small, while the quality factor Q is large. Thus, the difference between fmin and f0 can be neglected [11].

Bottom Line: Through the theoretical analysis of the sensor structure model, it is found that the increase in the dielectric constant and the decrease in the Young's modulus of DuPont 951 ceramic are the main causes that affect the pressure signal in high-temperature measurement.Through calculations, the Young's modulus of DuPont 951 ceramic is found to decrease rapidly from 120 GPa to 65 GPa within 400 °C.Finally, a temperature compensation structure is proposed and fabricated, and the pressure response after temperature compensation illustrates that temperature drift is significantly reduced compared with that without the temperature compensation structure, which verifies the feasibility the proposed temperature compensation structure.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Instrumentation Science & Dynamic Measurement, Ministry of Education, North University of China, Tai Yuan 030051, China. qinli@nuc.edu.cn.

ABSTRACT
In this work, a wireless passive LC resonant sensor based on DuPont 951 ceramic is proposed and tested in a developed high-temperature/pressure complex environment. The test results show that the measured resonant frequency varies approximately linearly with the applied pressure; simultaneously, high temperature causes pressure signal drift and changes the response sensitivity. Through the theoretical analysis of the sensor structure model, it is found that the increase in the dielectric constant and the decrease in the Young's modulus of DuPont 951 ceramic are the main causes that affect the pressure signal in high-temperature measurement. Through calculations, the Young's modulus of DuPont 951 ceramic is found to decrease rapidly from 120 GPa to 65 GPa within 400 °C. Therefore, the LC resonant pressure sensor needs a temperature compensation structure to eliminate the impact of temperature on pressure measurement. Finally, a temperature compensation structure is proposed and fabricated, and the pressure response after temperature compensation illustrates that temperature drift is significantly reduced compared with that without the temperature compensation structure, which verifies the feasibility the proposed temperature compensation structure.

No MeSH data available.