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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.


Calculated Young’s modulus of LTCC at different temperatures.
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sensors-15-16729-f008: Calculated Young’s modulus of LTCC at different temperatures.

Mentions: According to the expression of coefficient C, when the temperature increases from 20 °C to 400 °C, the ratio of a4 to d4 is seen as approximately invariable, whereas the variation of substrate ceramic permittivity causes the coefficient C to increase by a factor of only approximately 0.002, which differs from the substantial change of coefficient C. Therefore, it is inferred that the variation of substrate ceramic Young’s modulus could be the main reason causing the change. Ignoring the minimal change of dimensional proportion, variation of substrate permittivity etc minor factors, the coefficient C is found to be an inverse ratio with variable E. Thus, Young’s modulus of LTCC at different temperatures can be calculated approximately as:(12)E=C0CE0where E0 and C0 are Young’s modulus of LTCC and slope of the measuring curve at room temperature respectively [14]. Young’s modulus of LTCC at different temperatures can be derived. Figure 8 illustrates that the Young’s modulus of LTCC always decreases at elevated temperatures, especially above 300 °C. The Young’s modulus of LTCC is calculated to decrease to 65 GPa within 400 °C, which illustrates that the material becomes softened at high temperatures, causing the sensitive membrane to deform further under the same pressure.


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)

Calculated Young’s modulus of LTCC at different temperatures.
© Copyright Policy
Related In: Results  -  Collection

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

sensors-15-16729-f008: Calculated Young’s modulus of LTCC at different temperatures.
Mentions: According to the expression of coefficient C, when the temperature increases from 20 °C to 400 °C, the ratio of a4 to d4 is seen as approximately invariable, whereas the variation of substrate ceramic permittivity causes the coefficient C to increase by a factor of only approximately 0.002, which differs from the substantial change of coefficient C. Therefore, it is inferred that the variation of substrate ceramic Young’s modulus could be the main reason causing the change. Ignoring the minimal change of dimensional proportion, variation of substrate permittivity etc minor factors, the coefficient C is found to be an inverse ratio with variable E. Thus, Young’s modulus of LTCC at different temperatures can be calculated approximately as:(12)E=C0CE0where E0 and C0 are Young’s modulus of LTCC and slope of the measuring curve at room temperature respectively [14]. Young’s modulus of LTCC at different temperatures can be derived. Figure 8 illustrates that the Young’s modulus of LTCC always decreases at elevated temperatures, especially above 300 °C. The Young’s modulus of LTCC is calculated to decrease to 65 GPa within 400 °C, which illustrates that the material becomes softened at high temperatures, causing the sensitive membrane to deform further under the same pressure.

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.