Aiming at the accurate and rapid design of surface acoustic wave (SAW) filter with any complex film structure and the circuit topology, the hierarchical cascade model(HCT) is used to optimize and design the trapezoidal resonator and the dispersive COM model is used to optimize and design the longitudinal coupling resonators, based on the full-wave simulation platform of acoustic/electrical/magnetic multi-physical field coupling, combined with the genetic optimization algorithm and general graphics processor(GPGPU) acceleration technology. The forward design and optimization of SAW filters with arbitrary complex film structure and circuit topology are realized. The optimization design and development of a 42° Y-X LiTaO3 conventional SAW filter were carried out, and the design optimization results were in good agreement with experimental results, verifying the effectiveness and feasibility of the proposed method.

In this paper, a flexible surface acoustic wave device with “lithium niobate /benzocyclobutene(BCB)/ polyimide” structure is simulated and studied by finite element simulation method. The results show that the stable Rayleigh wave cannot be excited when the thickness of lithiumniobate(LN) is between 0.06λ~0.8λ, while outside this interval, Rayleigh waves can be excited. When the temperature increases, the resonant frequency of the device decreases. The calculation results show that the change of sound velocity with temperature is the main reason, which is greater than the frequency shift caused by thermal expansion. The simulation results in this paper provide a theoretical basis for the reasonable selection of piezoelectric film thickness and mechanical properties of substrate materials when designing and fabricating flexible surface acoustic wave devices.

In this paper, a third order differential bandpass filter with adjustable center frequency is presented. The filter uses the structure mainly consisting of a folded stub loaded resonator (FSLR) and a pair of folded parallel coupled lines to achieve filtering characteristics, at the same time, the microstrip-slotline conversion structure is used to excite the differential mode and suppress the common mode. Compared with the traditional microstrip filter, the common mode response of the proposed structure is independent of the differential mode response, so the good common mode suppression can be realized without reducing the differential mode performance, which makes the design more flexible. The overall size of the differential filter is 26 mm×49.2 mm, the center frequency is 3 GHz, and fractional bandwidth(FBW) is up to 28.67%, the level of common mode suppression is better than 37 dB. The results show that the measured results are in good agreement with the simulation ones.

In recent years, surface acoustic wave (SAW) temperature measurement technology has received wide attention because of its passive and wireless characteristics. This technology can be applied to the temperature measurement in the cable joints. However, the SAW temperature measurement signal transmission is hindered by the influence of the material and structure of the cable joints, which seriously affects the temperature signal detection. Based on the structure and material of DWG-630A cable joints, this paper designs an antenna that can be used for temperature measurement in cable joints. Through the theoretical analysis, simulation and experimental verification, it is verifies the design is practical. The results show that it is feasible to transmit SAW temperature signal through the cable joints and has good gain and radiation effect in the operating frequency band.

To address the assembly problem between heavy load and high detection resolution during the clamping and assembly of inertial confinement laser nuclear fusion (ICF) target parts, a micro-assembly method based on biaxial rotating structure is proposed in this paper. Firstly, by analyzing the characteristics of the assembly target devices(aluminum sleeve, gold cavity and half cavity), the overall structure scheme of precision assembly is formulated. Then, the dual-axis rotation device is introduced and the corresponding sensor is calibrated, and the angle deflection test of the dual-axis rotating device with integrated sensor is further carried out, which can detect a minimum deflection of 0.01°. The experiments show that the dual-axis rotation device can sensitively detect small deflections, and the sensor has the ability to “zero” for dual-axis rotation, through which the target assembly can be completed without visual guidance.

In order to solve the problem that the deformable lens based on edge drive cannot perform spherical aberration, an edge-driven double cavity deformable lens structure is proposed in this paper. There are 32 actuators in the upper cavity piezoelectric ring, which mainly correct the other low-order aberrations except the spherical aberration, mainly including the correction of defocus, astigmatism and coma. The lower cavity piezoelectric ring has one actuator, which realizes the correction of spherical aberration through the interaction with the upper cavity actuator. A testing platform for the deformable lens performance is actually set up and the experiment is carried out. The experimental results show that the proposed deformable lens can reconstruct the first four Zernike aberrations.

The basic structure of a single-axis MEMS thermal expansion flow gyro has been proposed, and its sensitive mechanism has been revealed in this paper. The three-dimensional model of the gyro was established by the finite element method using COMSOL Multiphysics, and the changes of temperature field and isotherm of the sensitive element of the gyro were calculated with and without angular velocity. The calculation results show that the single-axis MEMS thermal expansion flow gyro has the gyroscopic effect, and the structural sensitivity of the gyro is 0.053 9 K/［(°)·s-1］with a nonlinearity of 14.13% for the input angular velocity in the range of ［-1 080 (°)/s,1 080 (°)/s］.

In this paper, a high-sensitivity thermal expansion gyro was proposed, and its sensitive mechanism was studied. A 2D model of the structure was created by COMSOL, and the finite element analysis was carried out. The results show that when the input power is 5 mW, the input angular velocity range is -1 000-1 000 (°)/s, the proposed thermal expansion gyroscope has gyroscopic effect and its temperature sensitivity is 2.12 mK·［(°)/s］-1. When the input power is 5 mW, the input angular velocity range is -1 000-1 000 (°)/s, the sensitivity of the proposed thermal expansion gyro is 1.98 mV·［(°)/s］-1, and the nonlinearity is 7.64%. The gyro sensitivity is improved compared to the previous structure. The high-sensitivity thermal expansion gyro has the advantages of strong impact resistance, low production cost, simple process and high reliability, and can be used in aerospace, consumer electronics, military and other fields.

Due to the randomness of gravity anomalies, the accuracy of the sequence gravity matching algorithm is affected by the starting point position of the matching trajectory. To overcome this problem, a dynamic sequence gravity matching algorithm is proposed in this paper. This algorithm improves the gravity matching accuracy through the correlation extreme method by constructing a multi starting point matching trajectory sequence, dynamically selecting the starting points, and constructing a matching trajectory sequence. The algorithm has high gravity matching accuracy and good real-time performance, and can provide navigation information for underwater carriers for long-term navigation.

In order to improve the accuracy and reliability of the vehicle integrated navigation system, when the Global Navigation Satellite System (GNSS) signal is valid, a dual-antenna GNSS/MIMU/OD integrated navigation model is established and the on-line estimation of the error characteristics of miniature inertial measurement unit (MIMU) and odometer (OD) is realized. During the short-term interruption of the GNSS signal, a MIMU/dual OD integrated navigation model is established based on the dual OD wheel speed ratio correction (WRC) algorithm. The on-vehicle experimental results show that when the GNSS signal is interrupted for 120 s, the maximum positioning error is reduced by 63.9% and the standard deviation of positioning error is reduced by 80.1% compared with the model without WRC. When the GNSS signal is frequently interrupted for 200 s, the maximum position error is 0.55 m. The effectiveness of the established navigation model and algorithm on complex road conditions is verified.

In response to the demand for high-precision miniaturization of gyroscopes, a micro shell resonator gyroscope (mHRG) structure is designed in this paper. The three-dimensional finite element model is established and the effect of structural symmetry on the gyro performance is investigated. An evaluation method for the roundness of resonator and the asymmetric error of 1-4 order mass is proposed. The process of resonator fabrication is optimized, and the roundness error of the optimized resonator is ≤2 μm, on this basis, a micro shell resonator gyroscope (mHRG) prototype is developed. The performance of the encapsulated mHRG is tested.The results showed the circumference quality factor (Q) distribution is between (9.024-9.183)×105 with a uniformity of ±0.87%.In the force-rebalance mode, the gyroscope range is ±20 (°)/s , the bias instability (Allan deviation) of the gyroscope is 0.013 8 (°)/h, and the angle random walk(ARW) is 0.006 8 (°)/h. This study demonstrates the performance potential of the micro-hemisphere gyros with high structural symmetry.

The precession factor of hemispherical resonator gyroscopes (HRG) operating in the whole angle (WA) mode is only related to the spherical shell resonator. However, the detection errors such as the gap mismatch, the non-orthogonal coupling of the readout electrode and gain error of the detection circuit etc., will cause the circumferential consistency degradation of the precession factor. Thus the precession factor of ideal HRG is theoretically deduced firstly, then the influence of the detection errors on the precession factor is analyzed, and a correction method of the detection errors is proposed in the specific WA control circuit and algorithms. Finally, the effectiveness of the correction method is verified by experiments. The experimental results show that the circumferential consistency of the precession factor has been improved by two orders of magnitude.

In this paper, a hysteresis measurement experiment platform is built to measure the hysteresis effect of a piezoelectric actuator used for LED wafer detection.A piezoelectric hysteresis model based on LSTM neural network is designed, and the hysteresis effect of piezoelectric actuator displacement is modeled by time series prediction method.Comparing the model with the traditional PI model,the experimental results show that the model has better and more extensive hysteresis modeling effect. For sine wave, the displacement prediction accuracy is guaranteed to be within 2%, and for attenuated sine wave, it is guaranteed to be within 3%, which can basically meet the precision requirements of wafer detection in industry.

Lithium niobate (LiNbO3, LN) is a widely used dielectric material. Because of its large electro-optical coefficient, large transparent range and wide eigenband, it is extremely important in integrated and nonlinear optical devices. However, due to the good chemical stability and slow etching rate of lithium niobate on insulator (LNOI), the microstructure parameters are difficult to control. In view of the abovementioned problems, the preparation process of LNOI ridge microstructures based on inductively coupled plasma etching (ICP-RIE) was studied in this paper. The effects of chamber pressure, total gas flow and etching power on the etching rate, etching angle and surface roughness (RMS) were analyzed. The research shows that under the optimized process conditions, the etching rate of LNOI reaches 24.9 nm/min, and the LNOI ridge microstructure with etching depth of 249 nm, etching angle of 76 ° and surface roughness (RMS) of 0.716 nm is prepared. Through the study of etching process and microstructure parameters, this paper creates a LNOI microstructure etching method based on ICP, which provides technological support for controlling the LNOI ridge optical waveguide and improving its performance.

Taking the finger mortise-tenon joints and dovetail mortise-tenon joints as the research target, the experimental study on the damage detection of the mortise-tenon joints under health and damage conditions is carried out based on the piezoelectric active sensing technology. Specifically, the relaxation and defects for tenons with horizontal and vertical connections are considered as the damaged cases for finger joints, while the failure process caused by testing machine is considered as the damaged load case for dovetail joints. The wavelet packet decomposition of the signal received by the piezoelectric sensor is carried out, and the damage detection index calculated as the summation of signal energy for different frequency bands is used to evaluate the damage severity quantitatively. The experimental results indicate that the signal energy received by piezoelectric sensors for finger mortise-tenon joints gradually decreases with the increase of damage severity. For dovetail joints, the tenons are squeezed tightly against each other and then the tenon is damaged as a result of its semi-rigid characteristic, so the signal energy received by piezoelectric sensors for dovetail mortise-tenon joints increases firstly and then decreases with loadings. The experiment demonstrates that the piezoelectric active sensing technology can efficiently detect the damage of the mortise-tenon joints.It can provide an experimental method for nondestructive testing based on piezoelectric sensing technology for graduate students and engineering technicians in related majors.

As the nonlinear effect caused by the hysteresis of piezoelectric stack seriously restricts the improvement of system control accuracy, a piezoelectric control method based on compound control is proposed in this paper. The nonlinear error of the system is modeled and compensated, and the embedded drive design is realized based on the numerical control (NC) chip. The generalized PI model is used to model the controlled piezoelectric actuator, the exponential function is used as the density function, and the parameters of the envelope function and the density function are optimized based on the particle swarm optimization algorithm. Finally, the feedforward compensation inverse model of the piezoelectric actuator is obtained, and the compound control of the system is realized by combining the proportional integral control rate. At the same time, the control architecture of digital signal processing + field programmable gate array (DSP+FPGA) is adopted, which not only ensures the convenience of solving the inverse model in DSP, but also ensures the real-time and rapidity of sampling and closed-loop control in FPGA. The experimental results show that the proposed design method is correct and effective.

To address the problems of edge collapse and crashing in the chamfering process of non-standard crystal bulk and wafers, the side by side modular fixtures and vacuum adsorption disk components are designed to fix the product, and the 45° and arc cutters are designed, and then the single straight line and positive offset path are used for processing. The experimental results show that compared with the traditional chamfering process, the optimized process can greatly reduce the edge collapse and crashing during the chamfering process, and the unqualified rate is reduced from 14.78% to 3.09%, which is beneficial for batch production.

The pneumatic system is widely used in industrial production. When it works, the exhaust gas is directly passed into the atmosphere, resulting in wasting a large amount of energy. In this paper, the polyvinylidene fluoride (PVDF) piezoelectric plate is used as the core component of energy harvester to collect energy from the discharged compressed gas. A vibration energy harvester with multi-cantilever beam was designed, and the flow field of compressed gas entering the energy harvester was analyzed by ANSYS finite element simulation software, the power generation effect of piezoelectric plate was tested experimentally. The results show that the diameter of the incident port, the diameter of the spoiler column, the pressure of the incident port and the distance between the incident port and the spoiler column all affect the power generation effect of the piezoelectric plate. When the incident port pressure is 80 kPa and the load resistance is 900 kΩ, the total power of the energy harvester is up to 120.64 μW, which is 28.8% higher than that of other harvesters.

In order to meet the working requirements of low-frequency piezoelectric hydrophones, to address the self-noise optimization problem of piezoelectric hydrophones with pre-amplifiers, the equivalent noise model of two-port network is theoretically derived, and the SPICE model is established using LTSPIC to simulate the noise of key components. The low noise amplifier circuit is designed and manufactured based on the junction field effect transistor. The self-noise test on the designed amplifier and the hydrophone with pre-amplifier shows that the equivalent input noise of the amplifier is 8.48 nV/Hz@1 kHz, and the inflection point of 1/f noise is about 350 Hz, which is better than that of the existing integrated operational amplifier; the noise spectrum level of the hydrophone with pre-amplifier is 33.577 dB @1 kHz, which is lower than the zero-order sea state noise spectrum.

As the world's smallest navigation-grade gyroscope, the nuclear magnetic resonance (NMR) gyroscope has been received widespread attention at home and abroad. The NMR gyroscope determines the angular velocity of the carrier by detecting the change of the spin precession frequency of the nucleus in the magnetic field, and its accuracy is closely related to the uniformity and stability of the magnetic field. The navigation-grade NMR gyroscopes require an fT-level magnetic field environment, while high-efficiency magnetic shielding can generally achieve only 5 to 6 orders of magnitude of magnetic suppression, thus active magnetic compensation is also required. Based on the theoretical analysis of the magnetic field distribution of NMR gyroscope, the lateral magnetic compensation system is analyzed and studied by the mathematical calculation and computer simulation, and the lateral compensation coil is optimized and designed. The magnetic field uniformity of the designed gyroscope lateral compensation system is nearly about 13 times higher than before optimization, meeting the usage requirements of NMR gyroscope. This work provides a theoretical basis and reference value for the design and manufacture of nuclear magnetic resonance gyroscope.

In order to study the effects of different packaging conditions on the residual thermal stresses of low temperature co-fired ceramic (LTCC) substrate after packaging and welding, the thermal stress deformation of LTCC substrate under different temperature variation loads were simulated and tested in this work. The results show that the simulation results are in good agreement with the experimental results, which verified the feasibility of the numerical simulation for simulating the residual thermal stress of LTCC substrate after packaging and welding. On this basis, the simulation calculation of LTCC substrates corresponding to three typical working temperatures under the condition of zero expansion alloy bottom plate and silicon aluminum alloy packaging are carried out. The results show that the stress of LTCC on both sides of the LTCC substrate edge is concentrated and the residual stress in the middle is small, showing a warped state, while the thermal stress with silicon aluminum alloy packaging and welding is less than that of the zero expansion alloy packaging.

A new bistable energy harvester with a shaped hole in the cantilever beam substrate is designed to address the problem of high resonant frequency and rapid decrease in output voltage when deviating from the resonant frequency of the conventional linear piezoelectric cantilever beam energy harvester. The theoretical model of this energy harvester is established, an experimental prototype is fabricated, and the effect of magnetic spacing on the output voltage and operating band of the energy harvester under different external sinusoidal excitation frequencies is studied. The results show that the bistable effect of the bistable energy harvester with a shaped hole structure is enhanced and then weakened as the pole pair spacing decreases. From this, it is determined that the optimal pole pair spacing is 12 mm, the resonant frequency is 18 Hz, the maximum output root-mean-square (RMS) voltage reaches 12.01 V, the effective operating frequency of the harvester ranges from 15.5 Hz to 22.5 Hz, and the operating bandwidth reaches 7 Hz. The bistable energy harvester with shaped hole has a wider acquisition band and a higher output voltage response under the low-frequency vibration environments.

Compared with other piezoelectric materials, 1-3 piezoelectric single crystal composite materials have excellent piezoelectric properties and better acoustic matching properties, which are better for preparing high-performance ultrasonic transducers. In this paper, the vibration mode and impedance characteristics of the composites were systematically investigated by the finite element software COMSOL, and the high-frequency Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3(PIN-PMN-PT) ferroelectric single crystal/epoxy resin 1-3 composites were prepared by picosecond laser and their performance was characterized. The electromechanical coupling coefficient of the prepared 1-3 piezoelectric composites is 0.65, acoustic impedance is 19.96 MRayls. A high-frequency ultrasound transducer is fabricated by using the 1-3 composites. The transducer has center frequency of 17.68 MHz, -6 dB bandwidth of 84.38% and insertion loss of -25.4 dB.

To enrich the structure of macro-micro planar motion device, a basin type piezoelectric actuator was proposed in this paper. The 1st order in-plane symmetric bending vibration mode and 2nd order antisymmetric longitudinal vibration mode of the basin type structure were set as the working modes, and the piezoelectric ceramics adhered to the surface of the basin type actuator is used to excite the working modes vibration, forcing the driving feet to travel elliptically along the xOz and yOz planes simultaneously to push the moving bode. According to principle of transfer matrix mechanics, the vibration transfer equation of each element of the actuator is constructed, and by determining transfer conditions between the connecting elements and the piezoelectric boundary, a semi-analytical electromechanical coupling transfer matrix model of the actuator is established, and the solution program of the model was compiled. A multi-objective optimization mathematical model of the actuator was established to obtain its optimal sizes. To validate the semi-analytical model, a finite element model(FEM) of the actuator was also established. The working modal frequency differences obtained from the semi-analytical model and FEM model were 177 Hz and 191 Hz, respectively, and the driving foot’s vibration amplitude along x, y and z directions were 2.95 μm, 3.27 μm, 1.37 μm and 3.12 μm, 3.61 μm and 1.82 μm, respectively, which validated the effectiveness of the semi analytical model. The results indicate that the proposed actuator analysis method combining structural design with driving principles opens up a new idea for optimizing the performance of piezoelectric actuators.

The self-supported ZnO nanorods (ZnO NRs) @ reduced graphene oxide (rGO) composites were synthesized by a simple one-step hydrothermal method, and ZnO@rGO/polyvinylidene difluoride(PVDF) flexible composite film piezoelectric nanogenerators were prepared by spin-coating method. The studying results show that the output performance of the ZnO@rGO/PVDF flexible composite film piezoelectric nanogenerator increases first and then decreases with the ZnO@rGO doping mass. When the mass fraction of ZnO@rGO is 3.0 %, the output voltage and current of the ZnO/PVDF nanogenerator can reach 9.06 V and 0.74 μA, which are 120 % and 124 % higher than those of the ZnO/PVDF nanogenerator only doped with 3.0 %ZnO NRs, respectively. When the load resistance is 10 MΩ, the maximum output power of ZnO@rGO/PVDF flexible composite film piezoelectric nanogenerator is 5.79 μW. After 4 000 cycles of testing, the output performance of the prepared ZnO@rGO/PVDF flexible composite film piezoelectric nanogenerator is stable. The nanogenerator can monitor the walking and running posture of the human body and record the numbers of exercises. It is expected to be implanted into wearable electronic devices and used as self-powered pressure sensors.

Based on the Archimedes spiral equation, a piezoelectric actuator with equally spaced spiral electrodes is proposed in this paper. The electrode structure and driving principle of the actuator are analyzed. The spiral electrodes are fabricated by screen printing method, and the components to be tested are prepared. A displacement test platform was built to test the static performance of the element, and its static radial displacement and plane torsion angle were investigated. The experimental results show that under the action of sinusoidal excitation signal with frequency of 0.5 Hz and voltage of 200 V, the radial peak displacement of spiral electrode piezoelectric actuator with diameter of 25 mm, thickness of 2 mm, electrode width of 0.6 mm and electrode center distance of 1.2 mm can reach 1.02 μm, which is 1.57 times of that of traditional electrode piezoelectric actuator. The torsion angle can reach 0.12 mrad. Compared with the traditional piezoelectric actuator, the device has larger radial displacement output and produces obvious torsion angle.

The high-frequency medical ultrasonic imaging technology has been widely used in the observation of fine structures with human tissues due to its high spatial resolution, and 1-3 piezocomposite are the core of high-frequency ultrasonic transducer. The PZT ceramic micropillar array was sintered by the soft mold process to fabricate the PZT/epoxy 1-3 piezoelectric composite, and the microstructure observation and electrical properties characterization were carried out. The microstructure is complete and the electromechanical coupling coefficient reaches 0.64. A high-frequency ultrasonic transducer with center frequency of 20 MHz was designed and fabricated based on the prepared piezocomposite. The performance and the sound field of the transducer were tested by pulse echo method, and the ultrasonic imaging for the skin of human was carried out. The insertion loss and bandwidths of the transducer were 13.1 dB and 84.2%, respectively. It is indicated that the 1-3 piezocomposite via the soft mold process can make high-frequency ultrasonic transducer with low insertion loss and large bandwidth, which provides a low-cost and high-efficiency commercial way for the high-frequency medical ultrasonic transducers.

The BaZrO3 microwave dielectric ceramics with addition of x%B2O3 (x=0.5~5.0) were prepared using analytically pure BaCO3, ZrO2 and B2O3 as raw materials by traditional solid phase method. The effects of different B2O3 additions on microstructure, phase composition and microwave dielectric properties of BaZrO3 ceramics were studied by means of scanning electron microscope, vector network analyzer and X-ray diffractometer. The results show that the density sintering temperature, dielectric constant and dielectric loss decrease with the increase of B2O3 addition. The BaZr(BO3)2 phase precipitates when the added amount of B2O3 exceeds 1wt%. When the added amount of B2O3 is 3wt% and the sintering temperature is 1 300 ℃, BaZrO3 ceramics obtain excellent microwave dielectric properties, the dielectric constant εr=33.02, product of quality factor and frequency Q×f=32 761 GHz, temperature coefficient of resonant frequency τf=+152×10-6/℃.