AT-cut Quartz Crystal Resonator Research Articles

Analysis of amplitude and dissipation factor of AT-cut quartz crystal resonators over a wide temperature range

Analysis of amplitude and dissipation factor of AT-cut quartz crystal resonators over a wide temperature range

Automated mode chart generation for finite element analysis of piezoelectric resonators using principal component analysis based on clustering

This paper presents a new clustering method for identifying the vibration mode shapes of piezoelectric resonators using image processing and principal component analysis (PCA). The finite element method (FEM) is an indispensable tool for analyzing the vibration-displacement distribution of resonators and suppressing spurious vibration modes. Although the FEM exports eigenfrequencies as a list, including spurious vibration modes, recognizing the vibration shape of each eigenfrequency requires manual operation by operators to view the displacement distribution and identify the vibration shapes. The proposed method consists of a preprocessing step based on a threshold selection before the PCA step. Preprocessing significantly simplifies the vibration displacement distribution and reduces the amount of data required for post-processing PCA. The mode chart of the AT-cut quartz crystal resonator obtained using the proposed method agreed with Koga’s experimental results. The proposed method enables the generation of mode charts with reduced processing and computational resources.

The Multi-field Coupled Vibration Analysis of AT-Cut Quartz Crystal Resonators with Parallelism Error

The Multi-field Coupled Vibration Analysis of AT-Cut Quartz Crystal Resonators with Parallelism Error

A reusable QCR aptasensor for the detection of Brevetoxin-2 in shellfish

Brevetoxins (BTX) are pharmacologically active, lipid soluble cyclic polyether neurotoxins that are known to cause a wide range of neurological symptoms in humans.Harvesting and consumption of infected molluscs provide an entry point for BTXs into, the food chain, causing long-term health effects on accumulation for individuals, commonly in people with a compromised immune system and existing allergies. This study is an acoustic assay that has been constructed using a 9 MHz AT-cut quartz crystal resonator modified by attaching a specific single-stranded DNA aptamer. The DNA oligo modifies its conformation to attach itself to the binding site of the incoming BTX molecule resulting in a change in frequency on the QCR. A small Δf value was observed for lower concentrations of BTX indicating a small change in mass deposited on the crystal surface, while the opposite was true for higher concentrations. Cross-species behavior was evaluated using samples of similar origin, molecular weight and a combination of two toxins. The LOD of the fabricated QCR is 220 nM which is lower than the maximum recommended residue limit in food samples. Fresh mussel samples were spiked with known concentrations of BTX to evaluate its sensitivity in a food matrix. No interaction with other compounds was observed. Overall, this sensor finds potential application in the food sector (fishing units) where mussels are tested and graded for allergens and toxins before reaching the customer.

MEMS hydrogen gas sensor with wireless quartz crystal resonator

Abstract A highly sensitive hydrogen-gas sensor fabricated using MEMS technology is presented. The sensor chip consists of glass substrates, silicon substrate, and an AT-cut quartz crystal resonator, which is embedded in the microchannel constructed on the substrates. The quartz resonator has a fundamental resonant frequency of 165 MHz and a 200 nm palladium film deposited on its single surface as the hydrogen-gas sensing material. The MEMS hydrogen-gas sensor operates in a wireless manner by exciting and detecting the resonator vibration using the non-contacting antennas. The curvature induced resonant frequency change of the resonator plate caused by the expansion of the palladium film is used for the detection of the hydrogen gas. We succeeded in improving the hydrogen absorption rate and then the sensitivity for the hydrogen-gas detection by applying the air-plasma treatment method, and clarified the role of palladium oxide in lowering the energy barrier for the hydrogen-atom migration from surface to subsurface with the X-ray photoelectron spectroscopy. Thus sensitivity enhanced MEMS hydrogen-gas sensor exhibits a detection limit of 10 ppm or less at room temperature both in nitrogen and air.

Pressure Dependence of Viscosity for Methyl Oleate and Methyl Linoleate up to 400 MPa

In this work, the conductance versus sweep frequency for AT-cut quartz crystal resonators was measured for methyl myristate, methyl oleate, and methyl linoleate under high pressure. The response of resonators immersed in methyl myristate at each temperature (313 K, 333 K, and 353 K) was obtained at pressures up to 140 MPa. The obtained values were nearly similar for both the fundamental mode and third overtone, and the obtained viscosities agreed with the literature data up to 100 MPa. For methyl oleate and methyl linoleate, the pressure dependence of the viscosity at various temperatures (293 K, 313 K, 333 K, and 353 K) was obtained up to 400 MPa. The viscosity increased exponentially in the low-pressure region with increasing pressure, but the rate of increase slowed above ~ 150 MPa and the viscosity deviated from an exponential increase. Fitting was performed using a Tait-type equation, and the deviation from the fitted value was calculated using this fitting equation. The pressure dependence of the viscosity could be obtained within 10 % of absolute average deviation (AAD) with a sample volume of ~ 2 mL using simple experimental equipment.

Enhancement of sensitivity of Pd-based hydrogen-gas sensor by plasma exposure studied by wireless quartz resonator

Sensitivity of a hydrogen-gas sensor based on lattice expansion of palladium highly depends on the surface morphology of palladium. We find that the sensitivity can be significantly improved by exposing the as-deposited palladium film to low-power plasma. The hydrogen-gas detection was performed by a wireless-electrodeless AT-cut quartz-crystal resonator with 125 MHz fundamental resonance frequency. It detects hydrogen gas through bending deformation of the resonator caused by the volume expansion of palladium. The surface morphology of palladium film before and after the plasma treatment were analyzed using atomic force microscopy. The plasma treated palladium film exhibits a rougher surface, finer grains, voids, and grain boundary extension. Such morphology and structure changes along with defects induced by the ion bombardment during the plasma treatment strongly contribute to increase in hydrogen absorption rate and then the sensor sensitivity. We further investigate the thickness dependence of the sensitivity, revealing an optimum palladium film thickness of 300 nm.

Quartz Crystal Microbalance for viscosity measurement with temperature self-compensation

This paper presents the design, fabrication, and experimental demonstration of a portable viscosity measurement system using an AT-cut quartz crystal resonator with a temperature compensation technique. The proposed sensor is designed to measure viscosity from room temperature to 65 °C with complete temperature compensation. A novel fixture to hold the crystal for the viscosity sensing is designed using CAD (Computer Aided Design) software and a 3D model prototype was fabricated using a 3D printer. Subsequently, the fabricated fixture was integrated with a crystal resonator and tested with various mixtures of glycerol and water solutions each with different viscosities. A beat frequency based temperature measurement and compensation technique was also proposed and has been implemented in the crystal resonator based force measurement system in the literature. The measurement system is portable, simple, and low cost making it convenient for laboratory-based viscosity measurements. The proposed fixture of the measurement system can be altered for real-time monitoring to quantify the viscosity of the continuous flowing aqueous liquids.

Pressure Dependence of Bis(2-ethylhexyl) Sebacate and VG32 Hydraulic Oil Viscosities Using a Quartz Crystal Resonator

Conductances versus sweep frequencies for AT-cut quartz crystal resonators have been measured for bis(2-ethylhexyl) sebacate and several machine oils under high pressure. The frequencies versus viscosities of these liquids appeared on the correlation line between frequency shift and viscosity. The correlation line agreement is essentially a criterion for when quartz resonators may be used because non-Newtonian silicone oils deviated from the correlation line. The responses of resonators immersed in bis(2-ethylhexyl) sebacate were obtained at pressures up to 350 MPa. Viscosities were calculated from the resonance frequencies. The pressure dependence of the bis(2-ethylhexyl) sebacate viscosity agreed well with that obtained with the rolling ball method. By using reference liquids, it was found that resonator responses were independent of temperature over the range 295–372 K. Viscosity measurements for VG32 hydraulic oil were taken at pressures up to 250 MPa and at the temperature at which the commercial viscosity grade was defined [313 K (40 °C)].

Design, Modeling, and Experiment of a Piezoelectric Pressure Sensor Based on a Thickness-Shear-Mode Crystal Resonator

This paper presents the design, modeling, and experimental demonstration of a novel pressure sensor using an AT-cut quartz crystal resonator with beat frequency analysis-based temperature compensation technique. The combination of a compact design of the proposed pie-zoelectric crystal resonator structure and temperature compensation technique has advantages such as high accuracy, low cost, and good performance attributes. The sensor measures pressure and temperature simultaneously with a single AT-cut quartz resonator, thus avoiding the thermal lag problem in the commercial multiresonator-based pressure sensors. The pressure sensor is designed using computer-aided design software and CAE software (COMSOL Multiphysics). Finite-element analysis (FEA) of the pressure sensor is performed to analyze the stress–strain of the sensor's mechanical structure. A 3-D-printing prototype of the sensor was fabricated, and the sensing principle was verified using a force–frequency analysis apparatus. Subsequently, a full-up pressure sensor was fabricated with a stainless steel housing and a built-in crystal oscillator circuit. Based on the FEA and experimental results, we have determined that the maximum pressure the sensor can safely measure is 45 psi. Test results performed on the stainless steel product show a good linear relationship between the input (pressure) and the output (frequency).

Analysis and Validation of Contactless Time-Gated Interrogation Technique for Quartz Resonator Sensors.

A technique for contactless electromagnetic interrogation of AT-cut quartz piezoelectric resonator sensors is proposed based on a primary coil electromagnetically air-coupled to a secondary coil connected to the electrodes of the resonator. The interrogation technique periodically switches between interleaved excitation and detection phases. During the excitation phase, the resonator is set into vibration by a driving voltage applied to the primary coil, whereas in the detection phase, the excitation signal is turned off and the transient decaying response of the resonator is sensed without contact by measuring the voltage induced back across the primary coil. This approach ensures that the readout frequency of the sensor signal is to a first order approximation independent of the interrogation distance between the primary and secondary coils. A detailed theoretical analysis of the interrogation principle based on a lumped-element equivalent circuit is presented. The analysis has been experimentally validated on a 4.432 MHz AT-cut quartz crystal resonator, demonstrating the accurate readout of the series resonant frequency and quality factor over an interrogation distance of up to 2 cm. As an application, the technique has been applied to the measurement of liquid microdroplets deposited on a 4.8 MHz AT-cut quartz crystal. More generally, the proposed technique can be exploited for the measurement of any physical or chemical quantities affecting the resonant response of quartz resonator sensors.

Implementation of a Low-Cost Energy and Environment Monitoring System Based on a Hybrid Wireless Sensor Network

A low-cost hybrid wireless sensor network (WSN) that utilizes the 917 MHz band Wireless Smart Utility Network (Wi-SUN) and a 447 MHz band narrow bandwidth communication network is implemented for electric metering and room temperature, humidity, and CO2 gas measurements. A mesh network connection that is commonly utilized for the Internet of Things (IoT) is used for the Wi-SUN under the Contiki OS, and a star connection is used for the narrow bandwidth network. Both a duty-cycling receiver algorithm and a digitally controlled temperature-compensated crystal oscillator algorithm for frequency reference are implemented at the physical layer of the receiver to accomplish low-power and low-cost wireless sensor node design. A two-level temperature-compensation approach, in which first a fixed third-order curve and then a sample-based first-order curve are applied, is proposed using a conventional AT-cut quartz crystal resonator. The developed WSN is installed in a home and provides reliable data collection with low construction complexity and power consumption.

Synthesis, characterization and metal ion sensing properties of novel pyridone derivatives phthalocyanines

The design of novel substituted phthalocyanines closely follows the requirement of their planned applications. In this study, synthesize of novel pyridone derivatives metal-free and symmetrical cobalt(II) phthalocyanines was carried out to improve brightness. For this purpose; starting with 4-nitrophthalonitrile and 4-hydroxy-6-methyl-3-nitro-2-pyridone, 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile was prepared. Then 2(3),9(10),16(17),23(24)-tetrakis[6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy] metal-free phthalocyaninato and 2(3),9(10), 16(17),23(24)-tetrakis[6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy] phthalocyaninato Co(II) were synthesized by using 4-(6-methyl-3-nitro-2-oxo-1,2-dihydropyridin-4-yloxy)phthalonitrile, lithium metal and cobalt(II) acetate tetrahydrate in amyl alcohol, respectively. The sensing behavior of the film of derivatives metal-free and symmetrical cobalt(II) phthalocyanines for the online detection of heavy metal ions in water samples was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the analytes on the coating surface cause a reversible negative frequency shift of the resonator. Quartz crystal microbalance (QCM) functionalized with phthalocyanine, derivatives metal-free and symmetrical cobalt(II) phthalocyanines, are demonstrated to be sensors for the detection of heavy metal ions like Cd[Formula: see text], Zn[Formula: see text], Cu[Formula: see text], Cr[Formula: see text] and Co[Formula: see text]. Thus, QCM based sensor arrays are considered a promising platform for the direct analysis of aqueous samples.

Partition coefficient-Lewis basicity correlation in four dioxycyclobutenedion-bridged novel ball-type phthalocyanines

The novel ball-type bis-metallo [Zn(II), Co(II) and Cu(II)] phthalocyanines were synthesized from 4,4′-(3,4-dioxocyclobut-1-ene-1,2-diyl)-bis(oxy)] diphthalonitrile, which can be obtained by the reaction of 4-nitrophthalonitrile with 3,4-dihydroxy-3cyclobuten-1,2-dione. The novel ball-type phthalocyanines with cyclobutene unit were characterized by elemental analysis, UV–vis, FT-IR, 1H NMR, and MALDI-TOF mass spectroscopy. The response and recovery behaviours of the films to different analytes, which span a broad range of Lewis base, were investigated by utilizing an AT-cut quartz crystal resonator. Frequency changes during transient exposures to these vapours were rapid and reversible. The sensing behaviour of the films for a broad range of Lewis bases and the correlation between the partition coefficients and Lewis base enthalpies were investigated. Partition coefficients obtained from the linear response regimes of the calibration curves were in the 800–22,000 range. Results show that partition coefficients may be correlated exponentially with binding enthalpy.

100-MHz Low-Phase-Noise Microprocessor Temperature-Compensated Crystal Oscillator

An AT-cut third-overtone 100-MHz quartz crystal resonator was used to achieve a 100-MHz low-phase-noise voltage-controlled crystal oscillator prototype. The unloaded quality factor of the used resonator is about 132 K, and the equivalent dynamic capacitance is about 1.2 fF. For the characteristic of the large equivalent dynamic capacitance of the resonator, the design method and the actual measured data of the low-phase-noise oscillator prototype are given. An explanation of why larger equivalent dynamic capacitance and higher voltage-control sensitivity can lead to bad phase noise in half-bandwidth is given. The STM32F103RCT6 MCU is used to read the real-time data of temperature sensor of the microprocessor temperature-compensated crystal oscillator (MTCXO) and the real-time control voltage loading on the MTCXO. Therefore, the real-time communication between a personal computer and an MTCXO is achieved. The control voltage $V$ achieved in this way has already considered both the effect of the actual working condition of the MTCXO circuit and the effect of the MTCXO internal reference voltage that it is not accurate enough. After temperature compensation, the measured temperature performance of the 100-MHz low-phase-noise MTCXO are better than ±0.45 ppm/−30 °C –+50 ° C, and measured phase noise results are better than −157 dBc/Hz at 1 KHz and −170 dBc/Hz at 10 KHz.

Wide Range Load Sensor Using Quartz Crystal Resonator for Detection of Biological Signals

High-sensitive, wide-measurement range, and small-sized load sensor was developed using AT-cut quartz crystal resonator (QCR). The quartz crystal generates a charge, which is proportional to the external force. Since it has high sensitivity and excellent temperature stability, it has been used for various sensors. In particular, QCR has superior characteristic for static load sensing in nature. However, QCR is fragile and easily broken by the stress concentration. Moreover, a retention mechanism is required to transmit the load efficiently, and we have to fix the QCR firmly while avoiding off axis force. Miniaturization of the retention mechanism is quite difficult to develop, since fabrication and assembly process is complicated. We have proposed a miniaturized sensor element using microfabrication. The QCR load sensor had enormously wide range of force sensing over 10 4 . However, output of previous sensor changes easily by parasitic capacitance change around QCR. The objective of this paper is to improve the resolution of load measurement and stability of sensor output for detection of biological signals. We fabricated QCR sensor whose sensitivity is 973 Hz/N. We succeeded in detection of multiple biological signals (breath, heartbeat, and posture) using proposed QCR load sensor with high stability.

Quartz crystal microbalance (QCM) as biosensor for the detecting of Escherichia coli O157:H7

Although Escherichia coli (E. coli) is a commensalism organism in the intestine of humans and warm-blooded animals, it can be toxic at higher density and causes diseases, especially the highly toxic E. coli O157:H7. In this paper a quartz crystal microbalance (QCM) biosensor was developed for the detection of E. coli O157:H7 bacteria. The anti-E. coli O157:H7 antibodies were immobilized on a self-assembly monolayer (SAM) modified 5 MHz AT-cut quartz crystal resonator. The SAMs were activated with 16-mercaptopropanoic acid, in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and ester N-hydroxysuccinimide (NHS). The result of changing frequency due to the adsorption of E. coli O157:H7 was measured by the QCM biosensor system designed and fabricated by ICDREC-VNUHCM. This system gave good results in the range of 102–107 CFU mL−1 E. coli O157:H7. The time of bacteria E. coli O157:H7 detection in the sample was about 50 m. Besides, QCM biosensor from SAM method was comparable to protein A method-based piezoelectric immunosensor in terms of the amount of immobilized antibodies and detection sensitivity.

The Design of Constant Temperature Quartz Crystal Oscillator for Vehicle-Mounted Radar

According to the requirement of the vehicle-mounted radar and taking into consideration of main circuit, amplifying circuit, waveform conversion circuit, automatic gain circuit and voltage control circuit, and other factors of the AT-cut quartz crystal resonator. We designed a small single layer constant temperature high stability crystal vibration for vehicle-mounted radar.

Miniaturized load sensor using quartz crystal resonator constructed through microfabrication and bonding

Abstract Highly sensitive, wide-measurement-range compact load sensors are desirable for various applications, including measurement of biosignals, manipulation and stiffness measurement of cells, and so on. Conventional load sensors are highly sensitive but have relatively small measurement ranges. A load sensor using an AT-cut quartz crystal resonator (QCR) has superior characteristics such as, high accuracy, improved strength under compressive stress, long-term stability, and compact size. However, a retention mechanism is required to firmly support the QCR because the QCR is easily broken by stretching and bending motions. Conventional machining processes are not suitable for further miniaturization of the sensor. Even if the retention mechanism were miniaturized, the assembly process is complicated. In this paper, we propose a novel design and fabrication method for a load sensor using the QCR. Using microfabrication and bonding, the assembly process was simplified. We demonstrate the feasibility of a miniaturized QCR load sensor whose volume is 24.6 mm3 (width is 4 mm, height is 5.6 mm, depth is 1.1 mm). The experimental results showed that the nonlinearity and hysteresis were 0.94% F.S. and 1.68% F.S., respectively. Additionally, sensitivity of the sensor was 1458 Hz/N. We improved the sensitivity and stability of the sensor; the fluctuation was 0.04 mN over a period of 1 min. Moreover, the effects of the temperature change were evaluated. The temperature and the sensor output were linear within the range of 20°C–50°C.

Quartz force sensor and facing spiral coils for noncontact detection

A noncontact detectable force sensor is a promising technique for monitoring the defects of a structural object, such as buildings and bridges, and medical surgery devices. In this study, the noncontact detectable force sensor with an AT-cut quartz crystal resonator and a pair of spiral coils is proposed. The thickness-shear mode is excited with energy trapping excitation. The resonant frequency of this vibration mode is a function of the applied external force because of the nonlinear elastic module. Then, from the resonant frequency change of the quartz crystal, the input force can be measured. Admittance characteristics of this sensor contained series and parallel resonance. We confirmed that noncontact detection of the resonant frequency change is possible by using two facing spiral coils. The coil gap effect could be eliminated by calculating the difference between the series and parallel resonant frequencies.