High-Temperature Dielectric Properties of Aluminum Nitride Ceramic for Wireless Passive Sensing Applications

Liu, Jun; Yuan, Yukun; Ren, Zhong; Tan, Qiulin; Xiong, Jijun

doi:10.3390/s150922660

Cited by 18 publications

(7 citation statements)

References 20 publications

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“…where e, c and ε are the piezoelectric constant, elastic stiffness, and relative dielectric constant of AlN [20], respectively. Because as temperature increases, ε increases [21], and c decreases [16,21], the increase in K 2 t can be attributed to the increase in e of AlN [22]. The impact of h AlN on K 2 t of SAW sensors was investigated based on finite element method (FEM) simulation.…”

Section: Resultsmentioning

confidence: 99%

“…The elastic stiffness of AlN along aand m-directions has been reported previously [14]. However, the direction dependency of material parameter-tensors, including elastic stiffness [c ij ], piezoelectric constants [e ik ] and dielectric constants [ε ik ], is totally ignored, which is not physically reasonable [21]. In this paper, [c ij ] was extracted by fitting coupling of modes (COM) model simulation to experimental results of sensors along different directions, considering Euler transformation of parameter-tensors [23].…”

Section: 𝑐 = [𝛼] 𝑐 [𝛽]mentioning

confidence: 99%

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An Experimental and Theoretical Study of Impact of Device Parameters on Performance of AlN/Sapphire-Based SAW Temperature Sensors

Huang

et al. 2021

Micromachines

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The impact of device parameters, including AlN film thickness (hAlN), number of interdigital transducers (NIDT), and acoustic propagation direction, on the performance of c-plane AlN/sapphire-based SAW temperature sensors with an acoustic wavelength (λ) of 8 μm, was investigated. The results showed that resonant frequency (fr) decreased linearly, the quality factor (Q) decreased and the electromechanical coupling coefficient (Kt2) increased for all the sensors with temperature increasing from −50 to 250 °C. The temperature coefficients of frequency (TCFs) of sensors on AlN films with thicknesses of 0.8 and 1.2 μm were −65.57 and −62.49 ppm/°C, respectively, indicating that a reduction in hAlN/λ favored the improvement of TCF. The acoustic propagation direction and NIDT did not obviously impact the TCF of sensors, but they significantly influenced the Q and Kt2 of the sensors. At all temperatures measured, sensors along the a-direction exhibited higher fr, Q and Kt2 than those along the m-direction, and sensors with NIDT of 300 showed higher Q and Kt2 values than those with NIDT of 100 and 180. Moreover, the elastic stiffness of AlN was extracted by fitting coupling of modes (COM) model simulation to the experimental results of sensors along different directions considering Euler transformation of material parameter-tensors. The higher fr of the sensor along the a-direction than that along the m-direction can be attributed to its larger elastic stiffness c11, c22, c44, and c55 values.

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Section: Resultsmentioning

confidence: 99%

Section: 𝑐 = [𝛼] 𝑐 [𝛽]mentioning

confidence: 99%

An Experimental and Theoretical Study of Impact of Device Parameters on Performance of AlN/Sapphire-Based SAW Temperature Sensors

Huang

et al. 2021

Micromachines

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“…The total conduction heat loss was quantified as the linear combination of each thermal conveyor, and it is expressed by Eq. (20).…”

Section: Thermal Behaviormentioning

confidence: 99%

“…Aluminum Nitride (AlN) is a new generation of ceramic material whose main characteristics are high electrical resistivity and high thermal conductivity. Its outstanding heat dissipation is an essential characteristic in the high-power electronics industry where hightemperatures are inherent [17][18][19][20][21][22]. This section exposed the motivations for the present proposal on the design of a high-precision current transducer and the reasons for choosing the selected materials for its manufacture.…”

Section: Introductionmentioning

confidence: 99%

Design of a 1 ampere high-precision thin-film resistive current transducer with negligible frequency dependence from DC to 100 KHz

et al. 2020

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Currently, non-linear loads are found virtually anywhere with the promise of high electrical efficiency. Examples of this type of non-linear loads are compact fluorescent lamps and light-emitting diode lamps which can now be found in any home. However, they produce highly distorted currents that pollute the power grid and cause stability problems, and making the measurement of the distorted electrical current a non-trivial issue. For the reliable measurement of distorted waveforms within a wide bandwidth, magnetic current transducers present disadvantages over resistive current transducers, such as those caused by the magnetic material which attenuates the high-frequency components while producing heating on the magnetic material. This research presents the design principles to develop a thin-film wideband current transducer. Principles such as the selection of high-purity materials, high-symmetry coaxial design, size, geometry, and aspect ratios were used to obtain a linear relationship between its input and output, i.e.: a flat frequency response from DC to 100 kHz, and the ability to operate continuously with a custom passive thermal system for heat dissipation and reliable measurement. An exhaustive effort has been made on the refinement of the design aimed at understanding the effects that govern the frequency behavior of the transducer and the ways to compensate them. The manufacturing feasibility of the proposed design is well confirmed by the results obtained from the simulation process.

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“…The high-frequency simulator structure (HFSS) simulation software is used to verify the temperature-sensing mechanism. In the simulation using HFSS, the dielectric constant of the AlN ceramic material is set to range from 8.8 to 10.8 (the dielectric constant of the AlN ceramic material increases gradually with increasing temperature, so the dielectric constant is gradually increased) [ 44 ]. Figure 3 shows S 11 curves corresponding to different dielectric constants of the AlN substrate.…”

Section: Measurement Principlementioning

confidence: 99%

AlN-Based Ceramic Patch Antenna-Type Wireless Passive High-Temperature Sensor

et al. 2017

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An aluminum nitride (AlN) based patch antenna-type high-temperature wireless passive sensor is reported to operate as both a sensor and an antenna, which integrates in situ measurement/sensing with remote wireless communication at the same time. The sensor is small, easy to manufacture, highly sensitive and has a high operating temperature; it can be used in high-temperature, chemically corrosive and other harsh environments. The sensing mechanism of the sensor, the dielectric constant of the AlN ceramic substrate, increases with rising temperature, which reduces the resonant frequency of the sensor. Thus, the temperature can be measured by detecting changes in the sensor’s resonant frequency. High-Frequency Simulation Structure (HFSS) software is used to determine the structure and size of the sensor, which is then fabricated using thick-film technology. The substrate of the sensor is AlN ceramic due to its outstanding thermal resistance at high temperature; and its conductors (the radiation patch and the ground under the substrate) are silver-palladium alloy sintered form silver–palladium paste. A vector network analyzer reveals that the sensor’s operating range extends to 700 °C. Furthermore, its resonant frequency decreases from 2.20 GHz to 2.13 GHz with increasing temperature from room temperature (25 °C) to 700 °C, with an absolute sensitivity of 104.77 KHz/°C. Our work verifies the feasibility of measuring high temperatures using AlN-based patch antenna wireless passive temperature sensors, and provides a new material and temperature sensitive structure for high-temperature measurement in harsh environments.

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High-Temperature Dielectric Properties of Aluminum Nitride Ceramic for Wireless Passive Sensing Applications

Cited by 18 publications

References 20 publications

An Experimental and Theoretical Study of Impact of Device Parameters on Performance of AlN/Sapphire-Based SAW Temperature Sensors

An Experimental and Theoretical Study of Impact of Device Parameters on Performance of AlN/Sapphire-Based SAW Temperature Sensors

Design of a 1 ampere high-precision thin-film resistive current transducer with negligible frequency dependence from DC to 100 KHz

AlN-Based Ceramic Patch Antenna-Type Wireless Passive High-Temperature Sensor

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