Application of micromachined quartz tuning fork resonator for temperature sensing

This paper presents the design, fabrication and characterization of quartz tuning fork temperature sensor which is based on new ZY-cut-quartz crystal bulk acoustic wave resonator vibrating in a flexural mode. Design and performance analysis of the quartz tuning fork temperature sensor has been conducted and the thermal sensing characteristics were examined by measuring the resonance frequency shift of this sensor cause by an external temperature. The sensor prototype was successfully fabricated and calibrated from operating from 0°C to 100°C with sensitivity of 70ppm/°C. Experimental results show the sensor has high thermal sensitivity, good stability and well reproducibility. This work represents high precision and low power temperature sensor using the comprehensive thermal characterization of ZY-cut-quartz tuning fork resonator.

In order to optimize the design of quartz tuning fork temperature sensor, finite element method (FEM) is applied to model optimum tuning fork geometry, tine tip and tine surface electrode shape and thickness with a resonance frequency close to 32 kHz and a series resistance value of 40 kΩ as design targets. This type of sensor designed with a new ZYtw-cut is proved that working at flexural vibration mode was better than at the others modes. Precise temperature versus frequency analyses of resonators have been carried out and Least Mean Squared (LMS) curve fit algorithm is applied to compute the temperature values quantitatively. The results obtained from the experimental investigations show the method which synthesizes many factors to design quartz tuning-fork temperature sensor. Using ZYtw-cut can bring the temperature coefficient up to 70ppm/(degree C) and make power consumption lower. The temperature sensor based on quartz tuning-fork thermo-sensitive resonator is mounted in a standard holder for use from −30 degree C to 160 degree C with an accuracy of 0.05 degree C and a high resolution of 0.001 degree C. It is proved that it is possible to construct a miniature quartz tuning-fork temperature sensor with high sensitivity and small non-linearity.

In this paper, a low cost quartz tuning fork temperature sensor adopting H-shaped tuning fork resonator to address miniaturization, high resolution and high stability has been designed, developed and tested. The quartz tuning temperature sensor is designed vibrating in flexural mode with a new thermo-sensitive cut. The quartz tuning fork temperature sensor consists of two prongs connected at one end of crystalline quartz plate with thin-film metal electrodes deposited on the faces, which is used to produce vibration in response to alternating voltages and detecting the resonance frequency in the meantime. When an external temperature is change, there is a shift in its natural frequency. Based on this principle, a resonant thermometer is designed. Finite element method is used to analyze the vibratory modes and optimize the structure. The whole structure is 500μm thickness, the length of tuning fork arm is 3076μm and the width of tuning fork arm is 600um, the frequency of tuning fork is about 37kHz with a sensitivity of rough 85 ppm/°C. The experimental results shown that a temperature accuracy of 0.01 °C and a resolution of 0.005 °C within temperature range from 0 °C to 100 °C. All these research are helpful to design satisfactory performance of the sensor for temperature measurement.

This paper describes a novel quartz tuning fork temperature sensor, the principle of the quartz tuning fork temperature sensor is to detect resonance frequency shift by an external temperature. It has such advantages: high sensitivity, high accuracy, and good long-term stability. The temperature sensor is prepared of synthetic quartz on ZY-cut plates and configured by ZY-Cut quartz crystal wafer based tuning fork resonators whose operating frequency is at about 31 KHz. The characterization of a flexural mode tuning fork resonator which inherent frequency is sensitive to temperature changes is presented. Finite element method has been used in the deign process. The temperature frequency characteristic test system is setup. The temperature sensor is used to measure temperature in the range -50 Degree C-140 Degree C. The measurement results show that the tuning fork resonators based temperature sensor exhibits excellent sensitivity and short-term repeatability.

Quartz crystal is an elastomer with a natural oscillation frequency which can be served as a temperature sensor based on the resonance and thermal sensitivity subject to temperature when the forced vibration frequency is equal to its natural frequency. As a new type of temperature sensor, quartz crystal temperature sensor possesses high resolution, exact linearity and remarkable stability which could be used to measure temperature applied to moderate and low temperature environments. It is widely adopted in temperature measuring instruments under the circumstance of high-precision environments due to its availability of converting temperature signals to digital frequency signals. The oscillation frequency of the quartz fork resonator is extremely sensitive to the mass and stiffness of the quartz fork arm. Because of the electrode trench which can reflect the ambient temperature changes, it would be of special interest to design a temperature-sensitive quartz fork resonator for the study. The overall goal of this research is to study the surface electrode and quartz tuning fork temperature sensor in light of proposing an approach of temperature sensor design methodology, completing the sensor characteristic simulation, and designing the corresponding size of the sensor structure. Specific structure size: fork thickness 0.13mm, fork arm length 3mm, fork arm width 0.27mm, total length 5mm, total width 0.8mm.

This paper presents the design and fabrication of flexible skin conductance and temperature sensor using PDMS with a minimized skin contact area and increased device flexibility. The design and fabrication of reservoir-based (RB) drug delivery system (DDS) using microfabrication technology is also presented in this paper with possible future integration with these sensors. While the sensors can be used for the measurement of galvanic skin response for detecting emotional activity and monitoring of human stress in daily life, the RB-DDS can be used for delivering drug like insulin in a controlled and sustained manner to the target site. The sensor performance has been experimentally verified using the BITalino (r)evolution Board Kit while the DDS has been tested in-vivo and in-vitro. A comparative study on the sticking property of PDMS with aluminium was also conducted by exposing PDMS with oxygen and argon plasma.

A resonance temperature-sensing structure based on quartz tuning fork (QTF) is proposed and numerically investigated by using theoretical and numerical simulation in this paper. Reasonable selecting the quartz wafer cutting angle and Setting electrode configuration, the QTF resonator can be worked in flexural vibration mode. The numerical simulation results show that the change of the resonance frequency of the QTF is inversely proportional to the temperature changes with the environment. The structure of QTF resonator has been analyzed and optimized by the FEM software of ANSYS. Moreover, in order to investigate the thermal characteristic of QTF, A testing system of QTF has been successfully developed based on virtual instrument. The experimental results show that in the range from 0 °C to 100 °C, the thermal QTF as temperature sensor has a high thermo-sensitivity of -2.979 Hz/°C, hysteresis degree of 0.023%, linearity of 0.019% and resolution of 0.05°C respectively. Furthermore, after operation the test system features good stability and reliability, so it provides a feasible solution for test the characteristics of the sensor and can be applied to practice.

Human health is represented due to the measurement of vital signs. The basic vital signs are temperature, heart pulse rate, oxygen percentage in blood, blood pressure, etc. These signs are changes according to the physical and mental status of the individual. So measuring and monitoring those signs are very important. In this work, design and implementation of human Temperature Sensor are submitted. This is achieved using optical fiber technology. Two sensor diameters were tested; 125 µm and 60µm. The obtained results show a shifting in wavelength towards the red region due to temperature application. The submitted sensor has good sensitivity and linearity. Both sensors exhibit good responsivity, sensitivity, and high linearity. The sensitivity is increased about five times when the diameter is decreased.

The temperature sensitivity is one of the critical parameters for the thin film bulk acoustic resonator (FBAR) based temperature sensors. In this work, FBARs with Au/Fe0.8Ga0.2/Ti/AlN/Mo structure are developed. The size effect of the Ti insertion layer on the temperature sensitivity of the devices is systematically investigated. The devices were fabricated by MEMS process and characterized by a network analyzer under variable temperatures. It is found that the temperature sensitivity of the devices is strongly related to the thickness of the Ti insertion layer. A super-high temperature sensitivity up to 546 kHz °C−1 was obtained with 20 nm Ti inserted thin film; that feature can even reach 825 kHz °C−1 for some devices, showing great potential for ultra-sensitive temperature monitoring. Mason model is used to analyze the extraordinary characteristics of the device and finite element method (FEM) is used to analyze the strain distribution in the device. The supreme performance of the temperature sensor can be explained by the size effect of the temperature coefficient of Young’s modulus (TCE) of Ti film, which means that the TCE was enhanced when the thickness of the Ti film is around 20 nm. This work provides a new approach for the design of high sensitivity temperature sensor based on FBAR.

Quartz tuning fork temperature sensor with frequency as the output signal is a digital temperature sensor with high quality factor, low volume, low power consumption and other advantages, which plays an crucial role in the field of high-precision temperature measurement. To improve the performance of quartz tuning fork resonator, this paper proposes a quartz tuning fork temperature sensor with cut ZYlw(−10°,-41°) and optimizes its surface electrodes in order to reduce the parasitic effects generated at the tuning fork base. Simulation results show that for a new cut quartz temperature sensor we propose, the optimized electrodes exhibit good resonance characteristics with improved sensitivity and quality factor Q compared to the before optimization, especially the Q value is improved significantly by 12%.

Performance evaluation metrics for ring-oscillator-based temperature sensors on FPGAs: A quality factor

Recently, heat deposition rate measurements were reported that used a quasi-adiabatic double-shield graphite calorimeter. It was found that for a better understanding of nuclear heating due to incident radiation, having a calorimeter that could be conveniently moved axially and radially inside large material blocks would be advisable. Here, a simpler design, based on three elements, i.e., core, jacket, and shield is conceived. The fabrication and testing details are presented, and the performance of the current calorimeter is compared with a double-shield calorimeter under similar conditions. Such a system is found to be extremely sensitive and can be employed successfully at the LOTUS facility for future nuclear heat deposition rate measurements in large blocks of materials. The current design paves the way for the convenient testing of a large amount of kerma factor data required for constructing future fusion machines. The same configuration with minor changes can be extended to most of the fusion materials of interest. The core of the new calorimeter measures 11 mm in diameter and height and has overall dimensions of 24 mm in diameter and 180 mm in height. The response of the calorimeter is measured by placing it in front of the Haefely neutron generator. The reproducibility of these measurements is found to be better than 2.7% for a dose rate in the range of 30 to 100 cGy/min. The heating rates are found to vary linearly with the neutron source strength. Additional informationNotes on contributorsO. P. JonejaOm Parkash Joneja [MSc, Punjabi University, India, 1966; Training Sc School, Bhabha Atomic Research Centre (BARC), India, 1967; PhD, physics, University of Bombay, India, 1976] was scientific officer at BARC from 1967 to 1991. He is at present leader of the LOTUS activities at the Ecole Polytechnique Federate de Lausanne (EPFL) and is also conducting research in the advanced nuclear systems at the Paul Scherrer Institute, Villigen, Switzerland. His interests include development of nuclear techniques and theoretical and experimental investigations of the heat deposition rates in prototype fusion and fission systems.M. RosseletMarc Rosselet (Ingenieur Physicien, EPFL, Switzerland, 1994) worked on the development of the pencil-type graphite calorimeter for his diploma. He is presently working for his PhD on reactor kinetics problems and continues to have interest in the nuclear heat deposition measurements for validation of the kerma factor data relevant to fusion systems.J. LigouJacques P. Ligou (Diploma, electrical engineering, University of Toulouse, France; MS, nuclear physics, University of Lyon, France, 1950) worked for 10 years as a reactor physicist in the French nuclear industry. From 1969 to 1975 he was head of the Reactor Physics Section at the Swiss Federal Institute for Reactor Research. Presently, he is a professor of nuclear engineering at EPFL, and his main research interests lie in inertial confinement fusion and statistical physics.P. GardelPhilippe Gardel (PhD, physics, EPFL, Switzerland, 1991) worked as assistant at the Institute of Applied Radiophysics, Lausanne, Switzerland, from 1985 to 1991. He developed a graphite calorimeter for high-energy photon and electron beam absorbed dose measurements and made extensive comparative studies of dose measurements by calorimetric and ionometric methods. He is presently working as a consultant in statistical analysis and database system management. His present interest includes the application of calorimetric technique for heat deposition measurement in prototype fusion blankets.

The quartz tuning fork, initially designed for frequency control and clocks, has found a number of interesting applications due to its high stability and precision. It has seen use in scanning probe microscopy, force sensors, mass sensors, etc. As with most electromechanical resonators, the quartz tuning fork mainly uses resonant mode sensing in order to be used as a sensing device. Owing to its high quality factor, a shift in its natural frequency can be used to detect changes in the system’s parameters. In this work, the quartz tuning fork is modeled and examined through three-dimensional finite element analysis. The QTF exhibits an asymmetric behaviour in its frequency response due to parasitic capacitance. The parasitic capacitance of the resonator is examined analytically and experimentally, and later compensated to remove the asymmetry in its response. The experimental results are compared with the finite element simulations and with its widely used analytical model.

A dual-gas quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor system based on a frequency division multiplexing technique of a quartz tuning fork (QTF) was developed and experimentally demonstrated. Two beams from two independently modulated lasers are focused at two different positions between the QTF prongs to excite both the QTF fundamental and 1st overtone flexural modes simultaneously. The 2f-wavelength modulation technique is employed by applying two sinusoidal dithers, whose frequencies are equal to a half of the QTF fundamental and 1st overtone frequencies, respectively, to the currents of two excitation lasers. The resonance frequency difference between two flexural modes ensures that the correlated photoacoustic signals generated by different target gases do not interfere with each other. The proposed QEPAS methodology realizes a continuous real-time dual-gas monitoring with a simple setup and small sensor size compared with previous multi-gas QEPAS sensors.

A study of the dependence of main loss mechanisms on the geometry of piezoelectric quartz tuning forks (QTFs) is reported. The influence of these loss mechanisms on the quality factor Q occurring while the QTF vibrates at the in‐plane flexural fundamental and first overtone resonance modes is investigated. From this study, two QTFs efficiently operating both at the fundamental and first overtone mode are designed and realized. Data analysis demonstrates that air viscous damping is the dominant energy dissipation mechanism for both flexural modes. However, at the first overtone mode the air damping is reduced and higher quality factors can be obtained when operating at the first overtone mode with respect to the fundamental one.