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A Method of Design Dielectric Monoblock Filter with High Reliability
WEI Qiang, LI Kun, and FENG Xiaodong
A filter was designed based on elliptic function responses and fabricated using high-Q-factor monolithic ceramic materials with a relative permittivity of 37. A SMD monolithic four-cavity dielectric filter with low insertion loss was designed and manufactured by leveraging cascaded quadruplet coupling between 1 and 4 rA filter was designed based on elliptic function responses and fabricated using high-Q-factor monolithic ceramic materials with a relative permittivity of 37. A SMD monolithic four-cavity dielectric filter with low insertion loss was designed and manufactured by leveraging cascaded quadruplet coupling between 1 and 4 resonator, The performance indexes of the optimized filter are as follows: a center frequency of 1 268 MHz, operating bandwidth of 25 MHz, insertion loss ≤2.5 dB, return loss ≥18 dB, and out-of-band suppression ≥40 dB. On the basis of the structural parameters of the simulation model, samples were manufactured using the optimized metallization and molding process. The performance test results conform to the simulation results, demonstrating high reliability..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 143 (2024)
Research on Welding Technology for Ceramic Dielectric Filter
LI Yafei, ZHANG Junchong, GONG Xu, LI Yihong, TANG Panliang, CHEN Yanguang, and MA Jinyi
After observing the crack characteristics and analyzing the physical properties of the materials involved, improvements were implemented to address the issue of dielectric blank cracking during the assembly process of a ceramic dielectric filter. These enhancements comprised installing a metal shielding cover and modifAfter observing the crack characteristics and analyzing the physical properties of the materials involved, improvements were implemented to address the issue of dielectric blank cracking during the assembly process of a ceramic dielectric filter. These enhancements comprised installing a metal shielding cover and modifying the design of the printed board pad and reflow soldering process. Reliability tests of the welded device, including temperature and mechanical tests, were conducted, resulting in a product qualification rate of 100%. The analysis of DPA section revealed no risk of failure due to cracking or microcracking in the dielectric filter. The research findings indicate that this welding process effectively resolves the issue of welding cracks with ceramic dielectric filters, thereby achieving high product reliability..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 149 (2024)
Design and Preparation of High-Q XBARs
ZHANG Shuai, YU Zhenyi, GUO Yu, SUN Zongqin, FU Sulei, XU Zhibin, and WANG Weibiao
With the adventof the fifth generation(5G) mobile communication era, there is an urgent demand for high-frequency and large-bandwidth acoustic resonators for RF front-end filtering and signal processing. The laterally excited bulk wave resonator (XBAR) has garnered significant attention from researchers due to its ultrWith the adventof the fifth generation(5G) mobile communication era, there is an urgent demand for high-frequency and large-bandwidth acoustic resonators for RF front-end filtering and signal processing. The laterally excited bulk wave resonator (XBAR) has garnered significant attention from researchers due to its ultra-high operating frequency and substantial electromechanical coupling coefficient(k2). However, XBARs suffer from alow quality factor (Q), impeding their application in RF front-ends. This paper proposes XBARs based on ZY-cut lithium niobate (LiNbO3). Resonator designs were optimized using the finite element method, and resonators were fabricated using micro-electro-mechanical systems. The resulting XBAR exhibiteda resonant frequency of 4.72 GHz, k2 value of 26.9%, Q3 dB value of 384, and temperature coefficient of frequency of -60.5×10-6/℃ for the A1 mode, along with a resonant frequency of 13.5 GHzand k2 value of 4.4% for the A3 mode..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 154 (2024)
Simulation Analysis of a Thin-Film Bulk Acoustic-Wave Resonator for Spurious-Mode Suppression
LUO Enxiong, ZHANG Bizhuang, WU Kun, MA Jinyi, and LI Siren
In this study, the effect of the electrode-boundary step structure on the spurious mode of thin-film bulk acoustic resonators (FBARs) is investigated. The finite-element simulation method is used to investigate the effect of the width dimension of the step structure on the suppression of spurious modes. The step structIn this study, the effect of the electrode-boundary step structure on the spurious mode of thin-film bulk acoustic resonators (FBARs) is investigated. The finite-element simulation method is used to investigate the effect of the width dimension of the step structure on the suppression of spurious modes. The step structure is analyzed in conjunction with the vibration pattern to suppress the leakage of acoustic energy and to improve the quality factor of the device. To further verify the simulation results, FBAR devices are experimentally prepared. The results show that when the width of the raised frame is 3 μm and the width of the recessed frame is 1.5 μm, the resonator spurious mode is effectively suppressed and the quality factor at the anti-resonance frequency is increased by about 100..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 159 (2024)
Reliability Study on the Molding and Sintering Process of Microwave Ceramic Dielectric Filter
LI Yihong, LI Yafei, FENG Xiaodong, WEI Junjie, and PENG Shengchun
Starting with the microwave ceramic material NP37 itself, standard parts were pressed, and the effects of different molding pressures, sintering equipment (atmosphere furnace and tunnel furnace), and sintering temperature processes on the performance and reliability of the produced parts were investigated. This investiStarting with the microwave ceramic material NP37 itself, standard parts were pressed, and the effects of different molding pressures, sintering equipment (atmosphere furnace and tunnel furnace), and sintering temperature processes on the performance and reliability of the produced parts were investigated. This investigation involved density and electrical performance testing, as well as internal slice morphology observations. The optimal performance and reliability test results for a green body were achieved using a molding and sintering process with a forming pressure of 2 000 kg and a tunnel furnace temperature of 1 160 ℃. These conditions were applied to produce a dielectric filter body, and slice observations, scanning electron microscopy testing, thermal shock testing, and temperature shock testing confirmed the high reliability of this molding and sintering process. The results suggest that guiding the production of dielectric filters through the verification of the standard component molding and sintering process can effectively enhance product reliability..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 164 (2024)
Design of a New Multi-Function Centimeter Wave Frequency Synthesizer
MO Nei, YANG Hang, and MU Xiaohua
This paper proposes a novel multifunctional centimeter-wave frequency synthesizer. The proposed synthesizer, for the first time, moves the continuous wave (step:1 MHz), conventional pulse, double frequency jitter, double frequency stagger, double pulse, agile frequency conversion signal, group variable signal, two-phasThis paper proposes a novel multifunctional centimeter-wave frequency synthesizer. The proposed synthesizer, for the first time, moves the continuous wave (step:1 MHz), conventional pulse, double frequency jitter, double frequency stagger, double pulse, agile frequency conversion signal, group variable signal, two-phase coding, and linear frequency modulation signals from direct digital synthesis (DDS) to 0.8-18 GHz frequency band via phase-locked frequency doubling. The overall size of the device is 76 mm×70 mm×10 mm, and its volume is approximately one-twentieth that of the traditional frequency synthesizer. Thus, it affords the advantages of a wide working band, high frequency, and small size..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 171 (2024)
Research on Low-Frequency Miniaturized Lamb Wave Resonator
YE Changyu, XIAO Qiang, CHEN Zhenglin, DONG Jiahe, MI Jia, and BAO Jingfu
In pursuit of overcoming challenges hindering the miniaturization of low-frequency acoustic devices with extensive bandwidth, this study investigated the excitation of the antisymmetric A0 Lamb wave mode utilizing a Y-cut lithium niobate piezoelectric film. The finite element method was then used to examine the structuIn pursuit of overcoming challenges hindering the miniaturization of low-frequency acoustic devices with extensive bandwidth, this study investigated the excitation of the antisymmetric A0 Lamb wave mode utilizing a Y-cut lithium niobate piezoelectric film. The finite element method was then used to examine the structural design and conduct a theoretical analysis of the A0 mode. An assessment of various factors including lithium niobate cutting type, electrode material, metallization ratio, and film thickness variations on the acoustic velocity and electromechanical coupling coefficient revealed that the A0 mode Lamb wave exhibiteda lower acoustic velocity and larger electromechanical coupling coefficient compared to the conventional surface acoustic wave within a specific structure.This characteristic is advantageous for the miniaturization of low-frequency acoustic filters. Furthermore, we investigated the impact of different structures on the transverse mode of the resonator A0 mode Lamb wave to achieve clutter suppression..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 174 (2024)
Wide Stopband Cross-Coupled SIW Filter Based on Tooth-Shaped Ground Defect
SHE Jinchuan, WU Zhiqiang, WANG Kai, CHEN Yaozhong, CHEN Yan, LI Zhengxiong, and ZHANG Sheng
A low-pass transmission line structure with multi-level,tooth-shaped defects is proposed. The low-pass frequency and attenuation-band range could be effectively adjusted by varying the length of the branch of atooth-shaped defect. A wide-stopband filter with high out-of-band suppression was designed by cascading cross-A low-pass transmission line structure with multi-level,tooth-shaped defects is proposed. The low-pass frequency and attenuation-band range could be effectively adjusted by varying the length of the branch of atooth-shaped defect. A wide-stopband filter with high out-of-band suppression was designed by cascading cross-coupled fan-shaped SIW filters using this tooth-shaped defect ground structure. Compared to traditional SIW bandpass filters, the rectangular coefficient,K40 dB, had a value of two, and the stopband range was greater than twice the center frequency, demonstrating good passband and stopband selection characteristics. The test results showed that the filters center frequency was 10.35 GHz, with 3 dB and 40 dB bandwidths of 507 MHz and 1.05 GHz, respectively. The insertion loss was better than 1.47 dB, which was consistent with the simulation results..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 179 (2024)
Effect of Li、Ce Doping on NBTa-CBN High-Temperature Piezoelectric Ceramic Properties
XU Hongfei, SHI Wei, GUAN Shangyi, WU Yutong, and CHEN Qiang
A Ca0.5(Na0.5Bi0.5)0.5-3x(Li0.5Ce0.5)3xBi2TaNb0.99Mn0.01O9(CNBTNM-LC100x) solid-solution piezoelectric ceramic with high Curie temperature (TC) was prepared using the traditional solid-state reaction method. The effect of Li, Ce composite iondoping on the ceramic structure and electrical properties was studied. The resA Ca0.5(Na0.5Bi0.5)0.5-3x(Li0.5Ce0.5)3xBi2TaNb0.99Mn0.01O9(CNBTNM-LC100x) solid-solution piezoelectric ceramic with high Curie temperature (TC) was prepared using the traditional solid-state reaction method. The effect of Li, Ce composite iondoping on the ceramic structure and electrical properties was studied. The results show that, with increasing Li, Ce doping concentration, the crystal structure of CNBTNM-LC100x ceramics tends to transition from orthogonal to tetragonal, and the piezoelectric constant d33 gradually increases. When the molar fraction x>0.04, d33 tends to decrease. When x=0.04, the ceramic sample exhibits the best comprehensive performance, with d33≈15.9 pC/N, and the DC resistivity ρ≈5.9×105 Ω·cmat 600 ℃.Further,the dielectric loss tan δ(1 MHz)≈7%,and TC≈887 ℃..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 184 (2024)
Simulation Studyon High-Frequency and Low-Phase-Noise MEMS Oscillator Based on Lamb Wave Piezoelectric Resonator
ZHAO Ying, and CUI Xiangdong
With advancement in modern communication equipment, increasingly higher requirements are placed on clock source devices. These devices must exhibit the characteristics of integration and miniaturization while ensuring frequency signal stability. Microelectromechanical system(MEMS)oscillators, which conform to these reqWith advancement in modern communication equipment, increasingly higher requirements are placed on clock source devices. These devices must exhibit the characteristics of integration and miniaturization while ensuring frequency signal stability. Microelectromechanical system(MEMS)oscillators, which conform to these requirements,are gradually replacing traditional oscillators as signal sources in electronic equipment.This study entailed the design and simulation of a type of MEMS oscillator wherein the core frequency selection device is composed of a Lamb wave piezoelectric resonator. Prior to its application to anoscillator circuit, the designed MEMS resonator was simulated and tested, and two methods to optimize its parasitic mode were devised. Thus, a Q value of 1 357.5 and series resonance frequency of 70.384 MHz were obtained for the resonator. The optimized resonator was applied to anoscillator circuit, and the output signal and phase noise of the oscillator were tested. Consequently, MEMS oscillators with an output carrier frequency of 70.58 MHz and phase noises of -64.299 dBc/Hz@1 Hz and -144.209 dBc/Hz@10 kHz were obtained..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 191 (2024)
First Principles Study on Electronic Structure and Piezoelectricity of Mg-Doped ZnO
ZHANG Tao, LIU Yikun, GU Malong, YANG Longhai, and XI Yue
The electronic structure and piezoelectric properties of ZnO materials with different Mg doping contents were studied by first principles method. It is found that with the increase of Mg incorporation ratio, the ratio of ZnO lattice constant c to lattice constant a(c/a) decreases, and the band gap width increases. WhenThe electronic structure and piezoelectric properties of ZnO materials with different Mg doping contents were studied by first principles method. It is found that with the increase of Mg incorporation ratio, the ratio of ZnO lattice constant c to lattice constant a(c/a) decreases, and the band gap width increases. When the mole ratio of Mg doping is 0.3, the band gap reaches the maximum value of 1.493 eV. The calculation results of state density and differential charge density show that the reason for the increase of band gap is that the Zn-3d state in the conduction band moves towards the high-energy end. The introduction of Mg helps to improve the piezoelectric properties of ZnO materials, with the piezoelectric coefficient increasing from intrinsic 1.302 72 C/m2 to 1.355 88 C/m2. The increase of piezoelectric coefficient may be attributed to the structural distortion caused by the decrease in the value of the tetragonal factor c/a..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 197 (2024)
Design and Simulation of a Low-Temperature Sensitive Resonant Pressure Sensor
LI Guangxian, HUANG Jing, YUAN Yupeng, YANG Jing, LI Chunyang, ZHANG Zuwei, and LONG Shuai
To reduce the influence of the change in Young’s modulus with changes in temperature and thermal stress on the temperature drift of a resonant pressure sensor, a low-temperature-sensitivity resonant pressure sensor based on a Si-SiO2 composite H-shaped resonant beam and double resonator structure was designed. The finiTo reduce the influence of the change in Young’s modulus with changes in temperature and thermal stress on the temperature drift of a resonant pressure sensor, a low-temperature-sensitivity resonant pressure sensor based on a Si-SiO2 composite H-shaped resonant beam and double resonator structure was designed. The finite element simulation software COMSOL was used to simulate the sensor, and the results showed that the sensitivity of the sensor could reach 21.146 Hz/kPa in the range of 0-350 kPa, and the zero temperature drift in the range of -50 ℃ to +125 ℃ was as low as 0.2 Hz/℃. Compared with anall-silicon structure, the sensitivity temperature drift was reduced from 339×10-6/℃ to 14.1×10-6/℃, which could be adapted to anenvironment with a high operating temperature range..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 202 (2024)
Research on the Mechanism of an Independent Sensitive MEMS Thermal Expansion-Flow Gyroscope
LIU Junyu, PIAO Linhua, TONG Jiacheng, and MA Xuanlin
In this paper, a new independently sensitive micro-electromechanical system (MEMS) thermal expansion-flow gyroscope is proposed and its sensitivity mechanism is revealed. A three-dimensional model of the structure was created using the COMSOL multiphysics simulation software and finite-element calculations of the tempeIn this paper, a new independently sensitive micro-electromechanical system (MEMS) thermal expansion-flow gyroscope is proposed and its sensitivity mechanism is revealed. A three-dimensional model of the structure was created using the COMSOL multiphysics simulation software and finite-element calculations of the temperature field of its sensitive structure were performed. The computational results show that at a 50 mW heater power and an angular-velocity variation range of -10 rad/s-10 rad/s, this gyro has a gyroscopic effect with a temperature sensitivity of 0.224 K·(rad·s-1)-1 and a nonlinearity of 2.37%, and a sensitivity of 1.8 mV·(rad·s-1)-1 and a nonlinearity of 2.06%. This gyro has a high sensitivity and simple process. In addition, this study lays a theoretical basis for subsequent structure optimizations..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 207 (2024)
Variable-Friction Study Based on a Piezoelectric Ultrasonic Tactile Display
HAN Kai, LI Guoping, XIANG Sitong, CUI Yuguo, WEI Yanding, and LOU Junqiang
Using an ultrasonic lubrication mechanism and extrusion-film effect, a new piezoelectric ultrasonic tactile-display analysis model is proposed and theoretically and experiment allyanalyzed. Using a high extrusion number, the analytical expression of extrusion pressure was derived.A vibration-characteristic experiment wUsing an ultrasonic lubrication mechanism and extrusion-film effect, a new piezoelectric ultrasonic tactile-display analysis model is proposed and theoretically and experiment allyanalyzed. Using a high extrusion number, the analytical expression of extrusion pressure was derived.A vibration-characteristic experiment was conducted on the ultrasonic tactile-display analysis model and a qualitative and quantitative friction-discrimination experiment was carried out.The influence of the vibration frequency and excitation voltage on friction reduction was explored and the significant friction-reduction effect of the piezoelectric ultrasonic tactile-display analysis model was verified. This provides a theoretical basis for constructing a tactile-display shear-force model..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 213 (2024)
Research on the Cross-Fringe-Operation Error of FOGs
ZHAO Haibo, MO Nei, and LI Xudong
In interferometric fiber-optic gyroscopes(FOGs), when the modulation signal exceeds the limit and undergoes a 2π reset, a 2π phase difference appears between the modulation amount of the modulation-signal input and the input angular velocity.This causes the interference phase to shift left or right by 2π, i.e., a crossIn interferometric fiber-optic gyroscopes(FOGs), when the modulation signal exceeds the limit and undergoes a 2π reset, a 2π phase difference appears between the modulation amount of the modulation-signal input and the input angular velocity.This causes the interference phase to shift left or right by 2π, i.e., a cross-fringe operation. In a FOG closed-loop system, the error caused by the cross-fringe operation is reflected in the random-walk coefficient and nonlinearity. In this study, a cross-fringe error-cancellation mechanism is established by optimizing the modulation scheme, which can cause the cross-fringe errors to cancel each other, thus greatly improving the nonlinearity and random-walk coefficient. After simulated and physical verification, the results show the effectiveness of this method..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 219 (2024)
Study of an Improved 1-3-2 Type Piezoelectric Composite Material
JING Sujie, YU Zhaoxian, and WANG Hongwei
High-quality piezoelectric transducers require high electromechanical coupling coefficients and sensitivity.Based on the conventional 1-3-2 type piezoelectric composite material, an improved 1-3-2 type piezoelectric material is proposed to enhance the electromechanical coupling coefficient and receiving sensitivity of High-quality piezoelectric transducers require high electromechanical coupling coefficients and sensitivity.Based on the conventional 1-3-2 type piezoelectric composite material, an improved 1-3-2 type piezoelectric material is proposed to enhance the electromechanical coupling coefficient and receiving sensitivity of the piezoelectric transducer.The effects of different spacings on the resonance frequency, anti-resonance frequency, and electromechanical coupling coefficient of the sensitive elements of the improved 1-3-2 piezoelectric material are analyzed by finite-element simulation and compared with those of the traditional 1-3-2 piezoelectric composite material.The results show that the electromechanical coupling coefficient of the improved piezoelectric material is larger than that of the traditional 1-3-2 piezoelectric composite material with same spacing by approximately 0.03.Three improved piezoelectric materials with different spacings were fabricated.The results show that the improved piezoelectric material with a spacing of 1 mm has a large electromechanical coupling coefficient of about 0.68..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 223 (2024)
Design and Experimental Study of a Multi-Directional Vibration Harvester
LI Longfei, LUO Dabing, and LI Jintong
In response to the narrow working-frequency band and single-directional vibration capture of linear and single-mode vibration-energy harvesters, this paper proposes a novel multi-directional vibration-energy harvester that aims to enhance the capture of vibration energy in the environment. This device combines piezoeleIn response to the narrow working-frequency band and single-directional vibration capture of linear and single-mode vibration-energy harvesters, this paper proposes a novel multi-directional vibration-energy harvester that aims to enhance the capture of vibration energy in the environment. This device combines piezoelectric and electromagnetic energy harvesters. It effectively captures multi-directional vibrations through a spiral cylindrical spring and top mass and transfers the vibration energy to a piezoelectric beam through magnetic force. The spring-mass structure is designed to support multiple vibration modes at a lower frequency range, broadening the resonance-frequency band of the energy harvester. To fully utilize the piezoelectric material, the device implements a variable-width piezoelectric cantilever beam, ensuring a uniform stress distribution. The permanent magnet at the free end of the piezoelectric beam generates a changing magnetic field in response to the beam vibration, inducing a voltage in the coil. Through finite-element analysis and experimental testing, the composite energy harvester was verified to capture multi-directional vibration energy. Moreover, the maximum output power of the piezoelectric, electromagnetic, and composite energy harvesters under z-directional vibration excitation was tested. The composite energy harvester yields an output power of 3.276 mW when subjected to a 9.5 Hz sine-wave excitation with a 2 mm z-axis amplitude. This system offers continuous power for low-power sensors, thus providing technological support for mechanical energy harvesting and energy conversion..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 227 (2024)
Fast Electrical Impedance Spectroscopy-Based Characterization of Piezoelectric Material Using Artificial Neural Network
[in Chinese], and [in Chinese]
As important functional materials, piezoelectrics are widely used in various fields. However, the deviation of their elastic constants results in erroneous designs during application processes. Accurate characterization of the elastic constant is crucial for the correct design of piezoelectric devices.In contrast to otAs important functional materials, piezoelectrics are widely used in various fields. However, the deviation of their elastic constants results in erroneous designs during application processes. Accurate characterization of the elastic constant is crucial for the correct design of piezoelectric devices.In contrast to other measurement methods, electrical impedance spectroscopy can only be carried out using an impedance analyzer, and the elastic constants of piezoelectric materials can be obtained by the inversion of the impedance spectroscopy data.In traditional electrical impedance spectroscopy,the measured impedance spectra are coincided with the calculated impedance spectra to the best possible extent by constantly modifying the material parameters. However, the process requires many iterations, making it tedious and time consuming.This study developed a forward model that yields elastic constants from impedance spectra by harnessing an artificial neural network. Upon measuring the impedance spectrum, the elastic constant can be obtained by only one forward calculation.COMSOL and MATLAB co-simulation were used to generate the data-sets.The discard method was employed to avoid overfitting of the model, and Pytorch was used for implementation. The resonant frequency error was reduced from the initial 2.8% to 0.8% after training.The proposed technique affords a reliable theoretical and practical approach for accurately measuring the elastic constants of piezoelectric materials..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 234 (2024)
Design and Processing of Flexible Tri-Band Microstrip Antenna Using 3D Printing
ZHONG Zhidong, SHU Xiayun, CHANG Xuefeng, TANG Yiquan, and ZHU Shimin
A flexible tri-band microstrip antenna is proposed to address the issue of narrow wireless signal response ranges in wearable devices within complex application scenarios. This antenna employs a double “T”-shaped+double “L”-shaped surface structure to achieve resonance in the microwave frequency bands of 2.5 GHz, 3.5 GA flexible tri-band microstrip antenna is proposed to address the issue of narrow wireless signal response ranges in wearable devices within complex application scenarios. This antenna employs a double “T”-shaped+double “L”-shaped surface structure to achieve resonance in the microwave frequency bands of 2.5 GHz, 3.5 GHz, and 5.4 GHz. Polyimide serves as the substrate material, while nano-silver is utilized for the radiating patch, and aconductive material is applied on the ground plane to ensure flexibility. The antenna was analyzed using ANSYS HFSS to constructa model and conduct simulations. Fabrication utilized the microdroplet jet 3D printing process, effectively resolving the high cost and complexity associated with traditional MEMS processing in flexible electronics. Finally, field emission scanning electron microscopy was employed to analyze the printed surface morphology, and a vector network analyzer was utilized to test return loss, bendability, and fatigue resistance of the completed antenna. The test results were consistent with the simulation outcomes, demonstrating excellent bending performance of the antenna..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 241 (2024)
Research on Multi-Parameter High-Sensitivity Sweat Sensor Based on Flexible Film
ZHANG Yi, HUANG Jing, WEI Guiling, ZHANG Zuwei, and LI Xiaofei
This paper proposes a new high-sensitivity, multi-parameter sweat composition analysis sensor utilizing flexible thin film materials. The characteristics of the sensitive materials and high-sensitivity capture mechanism were studied and analyzed. Subsequently, an anti-interference signal acquisition circuit was designeThis paper proposes a new high-sensitivity, multi-parameter sweat composition analysis sensor utilizing flexible thin film materials. The characteristics of the sensitive materials and high-sensitivity capture mechanism were studied and analyzed. Subsequently, an anti-interference signal acquisition circuit was designed. Finally,a sample sensor was prepared, and a test environment was set up to test its key performance indicators. The results showed that the sweat sensor could realize the real-time monitoring of potassium ion, sodium ion, and glucose, which are components of sweat, with good detection-sensitivity and anti-interference-performance levels. The practicability was much better than that of atraditional detection instrument or single-parameter sweat-sensor detection method..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 246 (2024)
Design of Pyroelectric Protection Circuit for Piezoelectric Transducer
LI Shiguo, PAN Can, ZHAO Defeng, MU Jiangdong, LI Jun, and HE Zhiyi
This study explores the mechanism of the pyroelectric effect in piezoelectric materials and analyzes the polarization charge generated by temperature changes in the piezoelectric ceramic material employed in a piezoelectric transducer. It was observed that the resulting pyrovoltage heightened the output signal amplitudThis study explores the mechanism of the pyroelectric effect in piezoelectric materials and analyzes the polarization charge generated by temperature changes in the piezoelectric ceramic material employed in a piezoelectric transducer. It was observed that the resulting pyrovoltage heightened the output signal amplitude of the piezoelectric transducer, thereby compromising the output’s validity. Consequently, two solutions to mitigate the pyroelectric issue were investigated. Following a comparative analysis, an ESD protection circuit incorporating an enhanced diode clamp was devised. This circuit integrated a pyroelectric release loop to discharge the charge, effectively eliminating the impact of pyroelectric voltage on the transmission and reception of useful signals. Finally, the feasibility of the design scheme was verified by comparative experiments..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 253 (2024)
Design and Simulation of a Tilted Asymmetric Composite Piezoelectric-Energy Harvester
WANG Peng, JIANG Zihao, and CHEN Renwen
Vibration is a ubiquitous phenomenon in nature.Piezoelectric materials can convert the mechanical energy of external vibrations into electrical energy, providing energy for micro-electromechanical systems, wireless sensor networks, embedded systems, etc., thereby reducing the device’s dependence on battery power. To brVibration is a ubiquitous phenomenon in nature.Piezoelectric materials can convert the mechanical energy of external vibrations into electrical energy, providing energy for micro-electromechanical systems, wireless sensor networks, embedded systems, etc., thereby reducing the device’s dependence on battery power. To broaden the working bandwidth of the piezoelectric-energy harvester and improve its energy-harvesting efficiency, this study designs a tilted asymmetric composite piezoelectric-energy harvester, and obtains the natural frequency and modal shapes of each group of the harvester through theoretical analysis. Through finite-element analysis, the correctness of the theoretical derivation is proved, and the influence law of the number of piezoelectric cantilever beams on the piezoelectric-energy harvester in this design is verified. The results show that the tilted asymmetric composite piezoelectric-energy harvester can harvest vibration energy under multiple modes and improve the energy-harvesting efficiency..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 259 (2024)
Sensor-Layout Optimization Method Based on a Projectile Positioning Accuracy Analysis
XU Hong, XIE Yilin, GAO Qingsu, and CHEN Xiaolei
The rapid and accurate localization of impact points of supersonic projectiles on a target surface is a crucial factor influencing the performance of intelligent target-reporting systems. When obtaining projectile impact points by establishing an impact model, the sensor layout plays a vital role in determining the accThe rapid and accurate localization of impact points of supersonic projectiles on a target surface is a crucial factor influencing the performance of intelligent target-reporting systems. When obtaining projectile impact points by establishing an impact model, the sensor layout plays a vital role in determining the accuracy of the projectile impacts. In addressing the selection of the optimal sensor-layout method, this study proposes a projectile-impact-accuracy analysis method that combines a geometric dilution of precision analysis with optimization algorithms. This is achieved by calculating the area of iso-lines representing high-precision projectile impact points and searching for the optimal sensor layout within a specific range. The proposed method is validated through multiple sets of theoretical feasibility simulations, simulations with limited impact ranges under real conditions, and extended experiments. Results from these experiments reveal the fundamental principles governing sensor layouts for high-precision projectile impact localization. The effectiveness of the proposed projectile-localization accuracy analysis method is demonstrated by the successful selection of high-precision sensor layouts, with the identified optimal sensor layouts aligning with the fundamental principles of high-precision sensor deployment..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 264 (2024)
Piezoelectric Micro-Motion Platform Based on Hydraulic Amplification
XU Youxiong, ZHUANG Guangfeng, CHEN Xingyu, and LI Gongle
In response to the difficulty of traditional micro-motion platforms in meeting the requirements of micro/nano positioning, a two degree-of-freedom piezoelectric micro-motion platform based on hydraulic amplification is proposed and its structural design is created. The orthogonal design method was used to analyze the bIn response to the difficulty of traditional micro-motion platforms in meeting the requirements of micro/nano positioning, a two degree-of-freedom piezoelectric micro-motion platform based on hydraulic amplification is proposed and its structural design is created. The orthogonal design method was used to analyze the bidirectional fluid-structure coupling and optimize its structural parameters. A physical prototype was developed and experimental research was conducted. The open-loop experimental results show that when a 90 μm displacement is input into the piezoelectric actuator, the maximum displacement of the piezoelectric micro-motion platform is 603.0 μm, and the magnification is approximately 6.7. The closed-loop control experimental results show that using a segmented PID algorithm can reduce the overshoot, shorten the response and steady-state times, and reduce the steady-state error to ±0.2 μm. Thus, the micro-motion platform can realize precise large-scale positioning..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 273 (2024)
Process Method for Secondary Parallel Seal Welding
JI Yao, LIAO Wen, HE Weijie, TANG Kunlong, and WANG Chuanyao
Achieving secondary parallel sealing and meeting airtightness standards have become key to repairing airtight products. To solve this issue, this paper introduces a process method applied to secondary parallel seal welding. By laser uncapping the hermetically sealed components after parallel seal welding and controllinAchieving secondary parallel sealing and meeting airtightness standards have become key to repairing airtight products. To solve this issue, this paper introduces a process method applied to secondary parallel seal welding. By laser uncapping the hermetically sealed components after parallel seal welding and controlling the generation of wast ematerial, the surface of the shell enclosure is milled flat using machining. Finally, the secondary parallel seal is welded. The airtight-component system integration packaging (SIP) module is tested and analyzed to detect leaks after the secondary parallel seal welding. The leakage rate of less than 1.01×10-8 Pa·m3/s for the fine-leakage detection meets the requirements of electronic and electrical component test methods (GJB.360B-2009).There is no continuous bubble generation for rough leakage detection. Therefore, the process introduced in this paper can provide an effective solution for secondary parallel sealing airtight components with controllable waste material..
Piezoelectrics & Acoustooptics
- Publication Date: Aug. 29, 2024
- Vol. 46, Issue 2, 280 (2024)