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Micromachines
Volume 16
Issue 9
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Micromachines, Volume 16, Issue 9 (September 2025) – 88 articles

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15 pages, 4560 KB  
Article
Harmonic-Recycling Passive RF Energy Harvester with Integrated Power Management
by Ruijiao Li, Yuquan Hu, Hui Li, Haiyan Jin and Dan Liao
Micromachines 2025, 16(9), 1053; https://doi.org/10.3390/mi16091053 (registering DOI) - 15 Sep 2025
Abstract
The rapid growth of low-power Internet of Things (IoT) applications has created an urgent demand for compact, battery-free power solutions. However, most existing RF energy harvesters rely on active rectifiers, multi-phase topologies, or complex tuning networks, which increase circuit complexity and static power [...] Read more.
The rapid growth of low-power Internet of Things (IoT) applications has created an urgent demand for compact, battery-free power solutions. However, most existing RF energy harvesters rely on active rectifiers, multi-phase topologies, or complex tuning networks, which increase circuit complexity and static power overhead while struggling to maintain high efficiency under microwatt-level inputs. To address this challenge, this work proposes a harmonic-recycling, passive, RF-energy-harvesting system with integrated power management (HR-P-RFEH). The system adopts a planar microstrip architecture compatible with MEMS fabrication, integrating a dual-stage voltage multiplier rectifier (VMR) and a stub-based harmonic suppression–recycling network. The design was verified through combined electromagnetic/circuit co-simulations, PCB prototyping, and experimental measurements. Operating at 915 MHz under a 0 dBm input and a 2 kΩ load, the HR-P-RFEH achieves a stable 1.4 V DC output and a peak rectification efficiency of 70.7%. Compared with a conventional single-stage rectifier, it improves the output voltage by 22.5% and the efficiency by 16.4%. The rectified power is further regulated by a BQ25570-based unit to provide a stable 3.3 V supply buffered by a 47 mF supercapacitor, ensuring continuous operation under intermittent RF input. In comparison with the state of the art, the proposed fully passive, harmonic-recycling design achieves competitive efficiency without active bias or adaptive tuning while remaining MEMS- and LTCC-ready. These results highlight HR-P-RFEH as a scalable and fabrication-friendly building block for next-generation energy-autonomous IoT and MEMS systems. Full article
(This article belongs to the Special Issue Micro-Energy Harvesting Technologies and Self-Powered Sensing Systems)
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7 pages, 379 KB  
Editorial
Converging Architectures: Precision Biomanufacturing and Soft Robotics Rewiring Tissue Engineering
by Miriam Filippi
Micromachines 2025, 16(9), 1052; https://doi.org/10.3390/mi16091052 - 15 Sep 2025
Abstract
Biomedicine is moving from sculpting tissues to engineering systems [...] Full article
(This article belongs to the Section B2: Biofabrication and Tissue Engineering)
16 pages, 1848 KB  
Article
The Fluidic Shear Stress Loading Method Enables Mechanobiological Stimulation in an On-Chip Pump-Integrated Microphysiological System
by Jin Hong Yap, Satoshi Ishizaki, Hiroko Nakamura, Kenta Shinha and Hiroshi Kimura
Micromachines 2025, 16(9), 1051; https://doi.org/10.3390/mi16091051 - 15 Sep 2025
Abstract
Microphysiological systems (MPSs), such as organ-on-a-chip platforms, are promising alternatives to animal testing for drug development and physiological research. The BioStellar™ Plate is a commercial MPS platform featuring an open-top culture chamber design with on-chip stirrer pumps that circulate culture medium through six [...] Read more.
Microphysiological systems (MPSs), such as organ-on-a-chip platforms, are promising alternatives to animal testing for drug development and physiological research. The BioStellar™ Plate is a commercial MPS platform featuring an open-top culture chamber design with on-chip stirrer pumps that circulate culture medium through six independent, dual microchannel-connected chamber multiorgan units. Although this design enables a circular flow, the open-top culture chamber format prevents the application of fluidic shear stress, a force that cells experience in vivo, which affects their behavior and function. To address this, we developed two fluidic shear stress attachments for the BioStellar™ Plate. These attachment channel fluids provide controlled mechanical stimulation to cultured cells. The flow dynamics were simulated using COMSOL Multiphysics to estimate shear stress levels. The attachments were fabricated and validated through fluorescent bead tracking and biological assays. The FSSA-D is designed for flat-bottom standard cell cultures, while the FSSA-I is designed for epithelial monolayers, enabling the application of fluidic shear stress across the basal membrane. Experiments with intestinal epithelial cells (Caco-2) demonstrated that both attachments enhanced cell barrier function under a fluidic environment, as indicated by higher transepithelial electrical resistance (TEER). These findings demonstrate that the attachments are practical tools for mechanobiology research with MPS platforms. Full article
(This article belongs to the Special Issue Micro-/Nanofluidic and Lab-on-a-Chip Devices for Biomedical Applications, 3rd Edition)
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15 pages, 9265 KB  
Article
On-Machine Precision Truing and Error Compensation of Cup-Shaped Diamond Grinding Wheels with Arc-Shaped Cutting Edge
by Yawen Guo and Ziqiang Yin
Micromachines 2025, 16(9), 1050; https://doi.org/10.3390/mi16091050 - 15 Sep 2025
Abstract
The cup-shaped grinding wheels with arc-shaped edges provide a satisfactory precision grinding solution for high-accuracy optical surfaces on hard and brittle materials. However, the complex profile of the arc-shaped edges of cup-shaped grinding wheels makes them challenging to truing. This paper proposes an [...] Read more.
The cup-shaped grinding wheels with arc-shaped edges provide a satisfactory precision grinding solution for high-accuracy optical surfaces on hard and brittle materials. However, the complex profile of the arc-shaped edges of cup-shaped grinding wheels makes them challenging to truing. This paper proposes an on-machine truing technique targeting cup-shaped grinding wheels with arc-shaped cutting edge. First, a mathematical model was established to simulate the three-axis of on-machine truing the arc-shaped cutting edge using a diamond roller. Based on this model, a theoretical analysis is conducted to investigate the impact of tool setting errors, measurement errors of the diamond roller, and the pose error on truing accuracy. A compensation method was proposed, and experimental results validated its effectiveness. To investigate the grinding performance of cup-shaped grinding wheels after truing, a complex component is ground using a truing diamond grinding wheel. The experimental results demonstrate that this method enables precise on-machine truing of the arc-shaped edges of cup-shaped grinding wheels and is efficient. The average dimensional accuracy of the grinding wheel’s arc-shaped edge is reduced to 1.5 μm, with the profile accuracy (PV) of 0.89 μm. Full article
(This article belongs to the Special Issue Ultra-Precision Surface Abrasive Micro-Machining: Advances and Applications)
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13 pages, 14630 KB  
Article
Atomic Insight into the Nano-Grinding Mechanism of Reaction-Bonded Silicon Carbide: Effect of Abrasive Size
by Honglei Mo, Xie Chen, Cui Luo and Xiaojiang Cai
Micromachines 2025, 16(9), 1049; https://doi.org/10.3390/mi16091049 - 15 Sep 2025
Abstract
Reaction-bonded silicon carbide (RB-SiC) is a high-performance ceramic material known for its excellent mechanical, thermal, and chemical properties. It contains phases with different mechanical properties, which introduce complex machining mechanisms. In the present work, molecular dynamics (MD) simulation was conducted to investigate the [...] Read more.
Reaction-bonded silicon carbide (RB-SiC) is a high-performance ceramic material known for its excellent mechanical, thermal, and chemical properties. It contains phases with different mechanical properties, which introduce complex machining mechanisms. In the present work, molecular dynamics (MD) simulation was conducted to investigate the effect of abrasive size on the nano-grinding mechanism of RB-SiC. The surface morphology and subsurface deformation mechanism were investigated. The simulation results suggest that when a small abrasive is used, the surface swelling of SiC is primarily generated by the bending and tearing of SiC at the interfaces. As the abrasive radius increases, the surface swelling is mainly formed by Si atoms, which is identified as elastic recovery. Meanwhile, the material removal rate gradually decreases, and the depth of plastic deformation is obviously increased. Stocking of Si is more apparent at the interface, and obvious sliding of SiC grains is observed, forming edge cracks at the margin of the workpiece. In the subsurface workpiece, the high-pressure phase transition (HPPT) of Si is promoted, and the squeeze of disordered Si is obvious with more dislocations formed when larger abrasive is used. Full article
(This article belongs to the Special Issue Future Trends in Ultra-Precision Machining)
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11 pages, 2762 KB  
Article
Study on the Low-Damage Material Removal Mechanism of Silicon Carbide Ceramics Under Longitudinal–Torsional Ultrasonic Grinding Conditions
by Junli Liu, Zhenqi Ma, Yanyan Yan, Dengke Yuan and Yifan Wang
Micromachines 2025, 16(9), 1048; https://doi.org/10.3390/mi16091048 - 13 Sep 2025
Viewed by 41
Abstract
In order to achieve the high-performance machining of silicon carbide (SiC) ceramics, longitudinal–torsional ultrasonic vibration (LTUV) was introduced into precision machining, and a systematic investigation into the effects of various process parameters on the critical cutting depth and surface quality was conducted. This [...] Read more.
In order to achieve the high-performance machining of silicon carbide (SiC) ceramics, longitudinal–torsional ultrasonic vibration (LTUV) was introduced into precision machining, and a systematic investigation into the effects of various process parameters on the critical cutting depth and surface quality was conducted. This investigation was undertaken with a view to exploring the ultrasonic vibration-assisted grinding mechanism of SiC ceramics. Firstly, the kinematic model of single abrasive grain trajectory and the maximum unaltered cutting thickness during longitudinal–torsional ultrasonic vibration-assisted grinding (LTUVG) was established to explore its unique grinding characteristics. On this basis, the theoretical modeling of critical cutting depth in SiC ceramics under LTUVG conditions was developed. This was then verified through longitudinal–torsional ultrasonic scratching (LTUS) experiments, and the theoretical analysis and test results prove that compared with normal scratching, the quality of SiC grooves are significantly improved by means of LTUS. During LTUS experiments, the dynamic fracture toughness, strain rate of SiC, and high-frequency ultrasonic excitation significantly enhances SiC performance, increasing the critical cutting depth and expanding the plastic removal region, so it is easy for LTUVG to yield the better surface quality in machined SiC ceramics, which provides important scholarly support for achieving the low-damage machining of SiC ceramics. Full article
(This article belongs to the Special Issue Novel Processes for Cutting, Grinding and Polishing of Microstructured Surfaces)
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40 pages, 2695 KB  
Review
Morph and Function: Exploring Origami-Inspired Structures in Versatile Robotics Systems
by Tran Vy Khanh Vo, Tan Kai Noel Quah, Li Ting Chua and King Ho Holden Li
Micromachines 2025, 16(9), 1047; https://doi.org/10.3390/mi16091047 - 13 Sep 2025
Viewed by 48
Abstract
The art of folding paper, named “origami”, has transformed from serving religious and cultural purposes to various educational and entertainment purposes in the modern world. Significantly, the fundamental folds and creases in origami, which enable the creation of 3D structures from a simple [...] Read more.
The art of folding paper, named “origami”, has transformed from serving religious and cultural purposes to various educational and entertainment purposes in the modern world. Significantly, the fundamental folds and creases in origami, which enable the creation of 3D structures from a simple flat sheet with unique crease patterns, serve as a great inspiration in engineering applications such as deployable mechanisms for space exploration, self-folding structures for exoskeletons and surgical procedures, micro-grippers, energy absorption, and programmable robotic morphologies. Therefore, this paper will provide a systematic review of the state-of-the-art origami-inspired structures that have been adopted and exploited in robotics design and operation, called origami-inspired robots (OIRs). The advantages of the flexibility and adaptability of these folding mechanisms enable robots to achieve agile mobility and shape-shifting capabilities that are suited to diverse tasks. Furthermore, the inherent compliance structure, meaning that stiffness can be tuned from rigid to soft with different folding states, allows these robots to perform versatile functions, ranging from soft interactions to robust manipulation and a high-DOF system. In addition, the potential to simplify the fabrication and assembly processes, together with its integration into a wide range of actuation systems, further broadens its capabilities. However, these mechanisms increase the complexity in theoretical analysis and modelling, as well as posing a challenge in control algorithms when the robot’s DOF and reconfigurations are significantly increased. By leveraging the principles of folding and integrating actuation and design strategies, these robots can adapt their shapes, stiffness, and functionality to meet the demands of diverse tasks and environments, offering significant advantages over traditional rigid robots. Full article
14 pages, 3393 KB  
Article
Optical Sensor for Scanning Angle of Micromirror with Improved 2D Calibration Method
by Longqi Ran, Zhongrui Ma, Ting Li, Jiangbo He, Jiahao Wu and Wu Zhou
Micromachines 2025, 16(9), 1046; https://doi.org/10.3390/mi16091046 - 13 Sep 2025
Viewed by 47
Abstract
The optical angle sensor demonstrates considerable potential to supersede the piezoresistive sensor as the preferred angle detection mechanism for micromirrors, primarily due to its reduced vulnerability to temperature fluctuations. However, this sensor is susceptible to interference from rotations about non-detectable axes and exhibits [...] Read more.
The optical angle sensor demonstrates considerable potential to supersede the piezoresistive sensor as the preferred angle detection mechanism for micromirrors, primarily due to its reduced vulnerability to temperature fluctuations. However, this sensor is susceptible to interference from rotations about non-detectable axes and exhibits inadequate linearity. To mitigate these challenges, this paper introduces a sub-region calibration method. A mapping surface was created to link the output signal offsets of two axes with their input angles, allowing the effects of non-measured axes to be treated as variables. To simplify the mathematical model of this mapping surface, it was divided into an n-by-n grid of small areas. Each area uses bilinear interpolation to calculate the corresponding angle from the output values. To quickly locate which grid area a sensor output belongs to, the entire mapping surface was scaled to a range from 0 to n. Sensor outputs are then assigned to specific grid areas using the floor function. For validation, an optical sensor and a 2D rotating stage were built for calibration tests. Experimental results show that this calibration method keeps measurement errors below 0.01° within a ±8° operating range of the sensor. Full article
(This article belongs to the Special Issue Recent Advances in MEMS Mirrors)
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11 pages, 4467 KB  
Article
An Overmoded-Waveguide-Based Permittivity Measurement Method with High Accuracy and Ultra-Broadband over 8–110 GHz
by Weijie Wang, Yingjian Cao, Tieyang Wang, Fangfang Song, Shuanzhu Fang, Xianfeng Tang, Xiangqiang Li, Guoxiang Shu and Guo Liu
Micromachines 2025, 16(9), 1045; https://doi.org/10.3390/mi16091045 - 12 Sep 2025
Viewed by 109
Abstract
An overmoded-waveguide-based kit operating in 8–110 GHz for material complex permittivity measurement is proposed and designed in this paper. It overcomes the significant errors caused by air gaps in the conventional standard waveguide method (SWM), especially for millimeter-wave frequency bands. Furthermore, it avoids [...] Read more.
An overmoded-waveguide-based kit operating in 8–110 GHz for material complex permittivity measurement is proposed and designed in this paper. It overcomes the significant errors caused by air gaps in the conventional standard waveguide method (SWM), especially for millimeter-wave frequency bands. Furthermore, it avoids the problem of SWM requiring different samples in broadband measurements. The proposed kit consists of an overmoded-waveguide sample fixture with cross dimensions of 22.86 mm × 10.16 mm, seven pairs of standard-overmoded waveguide transition structures for different frequency bands, and thru-reflect-line calibration kits. The air gap problem, a major error source in millimeter-wave measurement, is quantitatively investigated. Compared with the SWM method, the proposed kit can decrease errors from over 68% to below 8%. The proposed method was verified by measuring the polytetrafluoroethylene sample. Then, it was applied to measure the BeO-TiO2 ceramic, which is widely used in vacuum devices. The measured data are valuable for applying BeO-TiO2 ceramics in relevant devices and developing its dielectric relaxation model. Full article
(This article belongs to the Special Issue Microwave Passive Components, 3rd Edition)
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17 pages, 4339 KB  
Article
Research on Cantilever Beam Roller Tension Sensor Based on Surface Acoustic Wave
by Yang Feng, Bingkun Zhang, Yang Chen, Ben Wang, Hua Xia, Haoda Yu, Xulehan Yu and Pengfei Yang
Micromachines 2025, 16(9), 1044; https://doi.org/10.3390/mi16091044 - 11 Sep 2025
Viewed by 155
Abstract
This paper presents a design method for a continuous tension detection sensor based on a cantilever beam structure and compensates for the temperature drift of a SAW sensor based on a neural network algorithm. Firstly, a novel cantilever beam roller structure is proposed [...] Read more.
This paper presents a design method for a continuous tension detection sensor based on a cantilever beam structure and compensates for the temperature drift of a SAW sensor based on a neural network algorithm. Firstly, a novel cantilever beam roller structure is proposed to significantly enhance the sensitivity of the transmission of silk thread tension to a SAW tension sensor. Secondly, to improve the sensitivity of the SAW tension sensor, the COMSOL finite element method (FEM) is employed for simulation to determine the optimal IDT placement. An unbalanced split IDT design is utilized to suppress potential parasitic responses. Finally, the designed sensor is tested, and a GA-PSO-BP algorithm is employed to fit the test data for temperature compensation. The experimental results demonstrate that the temperature sensitivity coefficient of the data optimized by the GA-PSO-BP algorithm is reduced by an order of magnitude compared to the raw data, with reductions of 6.0409×10−3 °C−1 and 3.0312×10−3 °C−1 compared to the BP neural network and the PSO-BP algorithm, respectively. The average output error of the optimized data is reduced by 5.748% compared to the sensor measurement data, and it is also lower than both the BP neural network and the PSO-BP algorithm. It provides new design ideas for the development of tension sensors. Full article
(This article belongs to the Special Issue Surface and Bulk Acoustic Wave Devices, 2nd Edition)
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19 pages, 4438 KB  
Article
Multi-Level Scale Attention Fusion Network for Adhesive Spots Segmentation in Microlens Packaging
by Yixiong Yan, Sijia Chen, Lian Duan, Dinghui Luo, Fan Zhang and Shunshun Zhong
Micromachines 2025, 16(9), 1043; https://doi.org/10.3390/mi16091043 - 11 Sep 2025
Viewed by 139
Abstract
The demand for high-quality beams from high-power lasers has led to the need for high-precision inspection of adhesion points for collimating lens packages. In this paper, we propose a Multi-Level Scale Attention Fusion Network (MLSAFNet) by fusing a Multi-Level Attention Module (MLAM) and [...] Read more.
The demand for high-quality beams from high-power lasers has led to the need for high-precision inspection of adhesion points for collimating lens packages. In this paper, we propose a Multi-Level Scale Attention Fusion Network (MLSAFNet) by fusing a Multi-Level Attention Module (MLAM) and a Multi-Scale Channel-Guided Module (MSCGM) to achieve highly accurate and robust adhesive spots detection. Additionally, we built a Laser Lens Adhesive Spots (LLAS) dataset using automated lens packaging equipment and performed pixel-by-pixel standardization for the first time. Extensive experimental results show that the mean intersection over union (mIoU) of MLSAFNet reaches 91.15%, and its maximum values of localization error and area measurement error are 21.83 μm and 0.003 mm2, respectively, which are better than other target detection methods. Full article
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25 pages, 1808 KB  
Review
Nanomaterial-Powered Biosensors: A Cutting-Edge Review of Their Versatile Applications
by Payal Patial, Manish Deshwal, Shonak Bansal, Anjana Sharma, Kamaldeep Kaur and Krishna Prakash
Micromachines 2025, 16(9), 1042; https://doi.org/10.3390/mi16091042 - 11 Sep 2025
Viewed by 223
Abstract
Optimal sensing devices exhibit a combination of key performance attributes, including an extensive detection limit, exceptional selectivity, high sensitivity, consistent repeatability, precise measurement, and rapid response times with efficient analyte flow. In recent years, biosensing platforms incorporating nanoscale materials have garnered considerable attention [...] Read more.
Optimal sensing devices exhibit a combination of key performance attributes, including an extensive detection limit, exceptional selectivity, high sensitivity, consistent repeatability, precise measurement, and rapid response times with efficient analyte flow. In recent years, biosensing platforms incorporating nanoscale materials have garnered considerable attention due to their diverse applications across various scientific and technological domains. The integration of nanoparticles (NPs) in biosensor design primarily bridges the dimensional gap between the signal transduction element and the biological recognition component, both of which operate at nanometer scales. The synergistic combination of NPs with electrochemical techniques has facilitated the development of biosensors characterized by enhanced sensitivity and superior analyte discrimination capabilities. This comprehensive analysis examines the evolution and recent advancements in nanomaterial (NM)-based biosensors, encompassing an extensive array of nanostructures. These consists of one-dimensional nanostructures including carbon nanotubes (CNTs), nanowires (NWs), nanorods (NRs), and quantum dots (QDs), as well as noble metal and metal and metal oxide nanoparticles (NPs). The article examines how advancements in biosensing techniques across a range of applications have been fueled by the growth of nanotechnology. Researchers have significantly improved biosensor performance parameters by utilizing the distinct physiochemical properties of these NMs. The developments have increased the potential uses of nanobiosensors in a wide range of fields, from food safety and biodefense to medical diagnostics and environmental monitoring. The continuous developments in NM-based biosensors are the result of the integration of several scientific areas, such as analytical chemistry, materials science, and biotechnology. This interdisciplinary approach continues to drive innovations in sensor design, signal amplification strategies, and data analysis techniques, ultimately leading to more sophisticated and capable biosensing platforms. As the field progresses, challenges related to the scalability, reproducibility, and long-term stability of nanobiosensors are being addressed through innovative fabrication methods and surface modification techniques. These efforts aim to translate the promising results observed in laboratory settings into practical, commercially viable biosensing devices that can address real-world analytical challenges across various sectors. Full article
(This article belongs to the Special Issue New Advances in Wearable and Flexible Sensor Devices and Their Future Prospects)
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1 pages, 129 KB  
Retraction
RETRACTED: Yang et al. Design and Dynamic Simulation of a Novel Traveling Wave Linear Ultrasonic Motor. Micromachines 2022, 13, 557
by Lin Yang, Kaixi Yao, Weihao Ren, Liang Chen, Mojian Yang, Rongcheng Zhao and Siyu Tang
Micromachines 2025, 16(9), 1041; https://doi.org/10.3390/mi16091041 - 11 Sep 2025
Viewed by 100
Abstract
The journal retracts the article “Design and Dynamic Simulation of a Novel Traveling Wave Linear Ultrasonic Motor” [...] Full article
28 pages, 3409 KB  
Article
Research on GNSS/MEMS IMU Array Fusion Localization Method Based on Improved Grey Prediction Model
by Yihao Chen, Jieyu Liu, Weiwei Qin and Can Li
Micromachines 2025, 16(9), 1040; https://doi.org/10.3390/mi16091040 - 11 Sep 2025
Viewed by 171
Abstract
To address the issue of decreased positioning accuracy caused by interference or blockage of GNSS signals in vehicle navigation systems, this paper proposes a GNSS/MEMS IMU array fusion localization method based on an improved grey prediction model. First, a multi-feature fusion GNSS confidence [...] Read more.
To address the issue of decreased positioning accuracy caused by interference or blockage of GNSS signals in vehicle navigation systems, this paper proposes a GNSS/MEMS IMU array fusion localization method based on an improved grey prediction model. First, a multi-feature fusion GNSS confidence evaluation algorithm is designed to assess the reliability of GNSS data in real time using indicators such as signal strength, satellite visibility, and solution consistency; second, to overcome the limitations of traditional grey prediction models in processing vehicle complex motion data, two key improvements are proposed: (1) a dynamic background value optimization method based on vehicle motion characteristics, which dynamically adjusts the weight coefficients in the background value construction according to vehicle speed, acceleration, and road curvature, enhancing the model’s sensitivity to changes in vehicle motion state; (2) a residual sequence compensation mechanism, which analyzes the variation patterns of historical residual sequences to accurately correct the prediction results, significantly improving the model’s prediction accuracy in nonlinear motion scenarios; finally, an adaptive fusion framework under normal and denied GNSS conditions is constructed, which directly fuses data when GNSS is reliable, and uses the improved grey model prediction results as virtual measurements for fusion during signal denial. Simulation and vehicle experiments verify that: compared to the traditional GM(1,1) model, the proposed method improves prediction accuracy by 31%, 52%, and 45% in straight, turning, and acceleration scenarios, respectively; in a 30-s GNSS denial scenario, the accuracy is improved by over 79% compared to pure INS methods. Full article
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16 pages, 4723 KB  
Article
A Novel Motion Platform Based on Dual Driving Feet Linear Ultrasonic Motor
by Yue Jian, Zhen Liu, Ping Yao, Wenjie Zhou, Junfeng He and Huazhuo Liang
Micromachines 2025, 16(9), 1039; https://doi.org/10.3390/mi16091039 - 10 Sep 2025
Viewed by 113
Abstract
This paper presents a novel motion platform based on a π-shaped linear ultrasonic motor. Initially, a new preload device was designed in accordance with established criteria for high-power linear ultrasonic motors. Mounted on the base structure, this mechanism neither interferes with the stator’s [...] Read more.
This paper presents a novel motion platform based on a π-shaped linear ultrasonic motor. Initially, a new preload device was designed in accordance with established criteria for high-power linear ultrasonic motors. Mounted on the base structure, this mechanism neither interferes with the stator’s high-frequency vibrations nor couples with the mover’s motion. Structural parameters were determined through theoretical modeling, while experimental validation confirmed the mechanism’s capability to deliver stable and appropriate preload throughout the motor’s complete operating cycle, thereby enhancing the platform’s operational stability and positioning accuracy. Subsequently, a novel mover was developed by replacing linear guides with a ceramic–ceramic mechanism. This mover features a compact structure and flexible design, facilitating both miniaturization and effective stroke amplification. The resulting platform achieves a 40% reduction in volume compared to conventional designs while extending the stroke to 150% of the original capacity. Finally, a prototype was fabricated and experimentally evaluated. Test results demonstrate output velocities exceeding 200 mm/s in both directions, with positioning accuracy reaching 1.1 μm. Full article
(This article belongs to the Section E：Engineering and Technology)
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21 pages, 3537 KB  
Article
Optimized Design of Sparse Antenna Array for 2D Subarrays Based on GA-PSO Algorithm and Ambiguity Function
by Jian Yang, Jian Lu, Tong Zhu, Chuanxiang Li and Yinghui Quan
Micromachines 2025, 16(9), 1038; https://doi.org/10.3390/mi16091038 - 10 Sep 2025
Viewed by 94
Abstract
A sparse antenna array of subarrays can effectively reduce the digital channels of array antennas, system complexities, and hardware cost while simultaneously increasing the antenna aperture. In this study, a new optimal design is proposed for a sparse antenna array of subarrays in [...] Read more.
A sparse antenna array of subarrays can effectively reduce the digital channels of array antennas, system complexities, and hardware cost while simultaneously increasing the antenna aperture. In this study, a new optimal design is proposed for a sparse antenna array of subarrays in the full-phased multiple input multiple output (FPMIMO) operation mode based on genetic algorithm–particle swarm optimization (GA–PSO) and ambiguity functions. The proposed algorithm can adaptively adjust the number of optimization iterations for yielding the optimization results of the PSO algorithm and GA to ensure the global optimization performance of algorithms and combine ambiguity functions to determine the final optimized sparse antenna array of subarrays. The effectiveness of the proposed algorithm is verified via simulation tests. Full article
(This article belongs to the Special Issue RF Devices: Technology and Progress)
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53 pages, 2691 KB  
Review
Heterogeneous Integration Technology Drives the Evolution of Co-Packaged Optics
by Han Gao, Wanyi Yan, Dan Zhang and Daquan Yu
Micromachines 2025, 16(9), 1037; https://doi.org/10.3390/mi16091037 - 10 Sep 2025
Viewed by 458
Abstract
The rapid growth of artificial intelligence (AI), data centers, and high-performance computing (HPC) has increased the demand for large bandwidth, high energy efficiency, and high-density optical interconnects. Co-packaged optics (CPO) technology offers a promising solution by integrating photonic integrated circuits (PICs) directly within [...] Read more.
The rapid growth of artificial intelligence (AI), data centers, and high-performance computing (HPC) has increased the demand for large bandwidth, high energy efficiency, and high-density optical interconnects. Co-packaged optics (CPO) technology offers a promising solution by integrating photonic integrated circuits (PICs) directly within or close to electronic integrated circuit (EIC) packages. This paper explores the evolution of CPO performance from various perspectives, including fan-out wafer level packaging (FOWLP), through-silicon via (TSV)-based packaging, through-glass via (TGV)-based packaging, femtosecond laser direct writing waveguides, ion-exchange glass waveguides, and optical coupling. Micro ring resonators (MRRs) are a high-density integration solution due to their compact size, excellent energy efficiency, and compatibility with CMOS processes. However, traditional thermal tuning methods face limitations such as high static power consumption and severe thermal crosstalk. To address these issues, non-volatile neuromorphic photonics has made breakthroughs using phase-change materials (PCMs). By combining the integrated storage and computing capabilities of photonic memory with the efficient optoelectronic interconnects of CPO, this deep integration is expected to work synergistically to overcome material, integration, and architectural challenges, driving the development of a new generation of computing hardware with high energy efficiency, low latency, and large bandwidth. Full article
(This article belongs to the Special Issue Emerging Packaging and Interconnection Technology, Second Edition)
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18 pages, 2420 KB  
Article
Variational Bayesian Innovation Saturation Kalman Filter for Micro-Electro-Mechanical System–Inertial Navigation System/Polarization Compass Integrated Navigation
by Yu Sun, Xiaojie Liu, Xiaochen Liu, Huijun Zhao, Chenguang Wang, Huiliang Cao and Chong Shen
Micromachines 2025, 16(9), 1036; https://doi.org/10.3390/mi16091036 - 10 Sep 2025
Viewed by 126
Abstract
Aiming at the issue of time-varying measurement noise with heavy-tailed characteristics and outliers generated by the polarization compass (PC) in the micro-electro-mechanical system–inertial navigation system (MEMS-INS) and PC-integrated navigation system when it is subject to internal and external disturbances, an improved Variational Bayesian [...] Read more.
Aiming at the issue of time-varying measurement noise with heavy-tailed characteristics and outliers generated by the polarization compass (PC) in the micro-electro-mechanical system–inertial navigation system (MEMS-INS) and PC-integrated navigation system when it is subject to internal and external disturbances, an improved Variational Bayesian Innovation Saturation Robust Adaptive Kalman filter (VISKF) algorithm is proposed. This algorithm utilizes the variational Bayesian (VB) method based on Student’s t-distribution (STD) to approximately calculate the statistical characteristics of the time-varying measurement noise of the PC, thereby obtaining more accurate measurement noise statistical parameters. Additionally, the algorithm introduces an innovation saturation function and proposes an adaptive update strategy for the saturation boundary. It mitigates the problem of innovation value divergence in PC caused by outliers through a two-layer structure that can track the changes in the innovation value to adaptively adjust the saturation boundary. To verify the effectiveness of the algorithm, static and dynamic experiments were conducted on an unmanned vehicle. The experimental results show that compared with adaptive Kalman filter (AKF), variational Bayesian robust adaptive Kalman filter (VBRAKF), and innovation saturate robust adaptive Kalman filter (ISRAKF), the proposed algorithm improves the dynamic orientation accuracy by 76.89%, 67.23%, and 84.45%, respectively. Moreover, compared with other similar target algorithms, the proposed algorithm also has obvious advantages. Therefore, this method can significantly improve the navigation accuracy and robustness of the INS/PC integrated navigation system in complex environments. Full article
(This article belongs to the Special Issue MEMS Inertial Device, 2nd Edition)
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12 pages, 4882 KB  
Article
Mg-Doped P-Type AlN Thin Film Prepared by Magnetron Sputtering Using Mg-Al Alloy Targets
by Yulin Ma, Xu Wang and Kui Ma
Micromachines 2025, 16(9), 1035; https://doi.org/10.3390/mi16091035 - 10 Sep 2025
Viewed by 168
Abstract
Aluminum nitride (AlN), a III-V wide-bandgap semiconductor, has attracted significant attention for high-temperature and high-power applications. However, achieving p-type doping in AlN remains challenging. In this study, p-type AlN thin films were fabricated via magnetron sputtering using Mg-Al alloy targets with varying Mg [...] Read more.
Aluminum nitride (AlN), a III-V wide-bandgap semiconductor, has attracted significant attention for high-temperature and high-power applications. However, achieving p-type doping in AlN remains challenging. In this study, p-type AlN thin films were fabricated via magnetron sputtering using Mg-Al alloy targets with varying Mg concentrations (0.01 at.%, 0.02 at.%, and 0.5 at.%), followed by ex situ high-temperature annealing to facilitate Mg diffusion and electrical activation. The structural, morphological, and electrical properties of the films were systematically characterized using X-ray diffraction (XRD), white light interferometry (WLI), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Hall effect measurements. The results demonstrate that at a Mg doping concentration of 0.02 at.%, the films exhibit optimal crystallinity, uniform Mg distribution, and a favorable balance between carrier concentration and mobility, resulting in effective p-type conductivity. Increasing Mg doping leads to higher surface roughness and the formation of columnar and conical grain structures. While high Mg doping (0.5 at.%) significantly increases carrier concentration and decreases resistivity, it also reduces mobility due to enhanced impurity and carrier–carrier scattering, negatively impacting hole transport. XPS and EDS analyses confirm Mg incorporation and the formation of Mg-N and Al-Mg bonds. Overall, this study indicates that controlled Mg doping combined with high-temperature annealing can achieve p-type AlN films to a certain extent, though mobility and carrier activation remain limited, providing guidance for the development of high-performance AlN-based bipolar devices. Full article
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12 pages, 10348 KB  
Article
The Effect of Dual-Layer Carbon/Iron-Doped Buffers in an AlGaN/GaN High-Electron-Mobility Transistor
by Po-Hsuan Chang, Chong-Rong Huang, Chia-Hao Liu, Kuan-Wei Lee and Hsien-Chin Chiu
Micromachines 2025, 16(9), 1034; https://doi.org/10.3390/mi16091034 - 10 Sep 2025
Viewed by 157
Abstract
This study compared the effectiveness of gallium nitride (GaN) with a single carbon-doped (C-doped) buffer layer and a composite carbon/iron-doped (C/Fe-doped) buffer layer within an AlGaN/GaN high-electron-mobility transistor (HEMT). In traditional power devices, Fe-doping has a large memory effect, causing Fe ions to [...] Read more.
This study compared the effectiveness of gallium nitride (GaN) with a single carbon-doped (C-doped) buffer layer and a composite carbon/iron-doped (C/Fe-doped) buffer layer within an AlGaN/GaN high-electron-mobility transistor (HEMT). In traditional power devices, Fe-doping has a large memory effect, causing Fe ions to diffuse outwards, which is undesirable in high-power-device applications. In the present study, a C-doped GaN layer was added above the Fe-doped GaN layer to form a composite buffer against Fe ion diffusion. Direct current (DC) characteristics, pulse measurement, low-frequency noise, and variable temperature analysis were performed on both devices. The single C-doped buffer layer in the AlGaN/GaN HEMT had fewer defects in capturing and releasing carriers, and better dynamic characteristics, whereas the composite C/Fe-doped buffers, by suppressing Fe migration toward the channel, showed higher vertical breakdown voltage and lower sheet resistance, and still demonstrated potential for further performance tuning to achieve enhanced semi-insulating behavior. With optimized doping concentrations and layer thicknesses, the dual-layer configuration offers a promising path toward improved trade-offs between leakage suppression, trap control, and dynamic performance for next-generation GaN-based power devices. Full article
(This article belongs to the Special Issue III–V Compound Semiconductors and Devices, 2nd Edition)
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9 pages, 5512 KB  
Article
Design of N-Way Power Divider Based on TE10 Mode Splitting Strategy
by Jianfeng Chen, Haidi Tang, Shengqi Zhang and Leijun Xu
Micromachines 2025, 16(9), 1033; https://doi.org/10.3390/mi16091033 - 10 Sep 2025
Viewed by 200
Abstract
This paper presents a novel 1-to-N power division architecture combining overmoded TE10 mode waveguides and modular N-way waveguide-to-microstrip mode converters. By decomposing the TE10 mode field distribution along the narrow wall of a rectangular waveguide, the proposed design enables [...] Read more.
This paper presents a novel 1-to-N power division architecture combining overmoded TE10 mode waveguides and modular N-way waveguide-to-microstrip mode converters. By decomposing the TE10 mode field distribution along the narrow wall of a rectangular waveguide, the proposed design enables flexible power splitting into arbitrary output ports (even or odd numbers) through uniform sub-TE10-mode waveguide pathways. To achieve the above function using microwave transmission lines, a tapered transition structure ensures wideband excitation of the overmoded waveguide, while linearly tapered slot antennas (LTSAs) serve as N-way mode converters. Prototypes with two-, three-, and four-channel outputs demonstrate excellent amplitude-phase uniformity (≤0.5 dB amplitude imbalance and ≤5∘ phase deviation) across 6.5–12 GHz, with return loss <−10 dB. The modular 1-to-N power divider enables the rapid reconfiguration of output channels by simply replacing the mode converter module. Full article
(This article belongs to the Special Issue Electromagnetic Metamaterials and Metasurfaces: From Design to Applications)
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12 pages, 2523 KB  
Article
Lightweight Design Method for Micromanufacturing Systems Based on Multi-Objective Optimization
by Shan Li and Seyed Hamed Hashemi Sohi
Micromachines 2025, 16(9), 1032; https://doi.org/10.3390/mi16091032 - 9 Sep 2025
Viewed by 258
Abstract
This study proposes a multi-stage collaborative design framework integrating sensitivity analysis, response surface methodology (RSM), and topology optimization for synergistic lightweighting and performance enhancement of micromanufacturing systems using ultra-precision computer numerical control (CNC) machine tools. Overall sensitivity analysis identified the base and column [...] Read more.
This study proposes a multi-stage collaborative design framework integrating sensitivity analysis, response surface methodology (RSM), and topology optimization for synergistic lightweighting and performance enhancement of micromanufacturing systems using ultra-precision computer numerical control (CNC) machine tools. Overall sensitivity analysis identified the base and column as stiffness-critical components, while the spindle box exhibited significant weight-reduction potential. Using spindle box wall and bottom thickness as variables, RSM models for mass and stress were constructed. Multi-objective optimization via a genetic clustering algorithm achieved a 57.2% (590 kg) weight reduction under stress constraints (<45 MPa). Subsequent variable-density topology optimization (SIMP model) reconfigured the rib layouts of the base and column under volume constraints, reducing their weights by 38.5% (2844 kg) and 41.5% (1292 kg), respectively. Whole-machine validation showed that maximum static deformation decreased from 0.17 mm to 0.09 mm, maximum stress reduced from 58 MPa to 35 MPa, and first-order natural frequency increased from 50.68 Hz to 84.08 Hz, significantly enhancing dynamic stiffness. Cumulative weight reduction exceeded 3000 kg, achieving a balance between lightweighting and static/dynamic performance improvement. This work provides an effective engineering pathway for a structural design of high-end micromanufacturing systems. Full article
(This article belongs to the Special Issue Ultra-Precision Surface Abrasive Micro-Machining: Advances and Applications)
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13 pages, 3362 KB  
Article
Gate-Induced Static and Dynamic Nonlinearity Characteristics of Bilayer Graphene Field-Effect Transistors (Bi-GFETs)
by Varun Kumar Kakar, Munindra and Pankaj Kumar Pal
Micromachines 2025, 16(9), 1031; https://doi.org/10.3390/mi16091031 - 9 Sep 2025
Viewed by 403
Abstract
In this study, the nonlinearity characteristics of bilayer graphene field-effect transistors (Bi-GFETs) are analyzed by using a small-signal equivalent circuit. The static nonlinearity is determined by applying mathematical operation on the drain current equation of Bi-GFETs. Furthermore, the closed expressions for the second- [...] Read more.
In this study, the nonlinearity characteristics of bilayer graphene field-effect transistors (Bi-GFETs) are analyzed by using a small-signal equivalent circuit. The static nonlinearity is determined by applying mathematical operation on the drain current equation of Bi-GFETs. Furthermore, the closed expressions for the second- and third-order harmonic distortion (HD) and the intermodulation (IM) distortion of the second- and third-order for Bi-GFETs are analyzed graphically. Dynamic nonlinearity is studied and illustrated in the results by examining the input and output characteristics; i.e., the drain current versus the negative drain to the source voltage and the transfer characteristic curve at various gate voltages controlled by both the top gate as well as the back gate. The characteristic behavior of the gate voltage in Bi-GFETs at short channel lengths is observed and compared; that is, the characteristic curves exhibits strong nonlinearity, with a low power point with some kinks at high gate biasing and a constant linear region at low gate biasing. The quantitative values of the second-order harmonic distortion (HD) and intermodulation distortion (IM) of the proposed analytical model are −40 dB and −45 dB. Quantitative and qualitative outcomes of the characteristics of Bi-GFETs are compared with existing experimental data, which is available in the literature. Full article
(This article belongs to the Special Issue Wide-Bandgap Semiconductor Devices: Materials, Fabrication, and Applications, 2nd Edition)
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13 pages, 7927 KB  
Article
Dual-Mode Reconfigurable Frequency-Selective Surface for Switching Between Narrowband and Wideband Applications
by Batuhan Uslu, Sena Esen Bayer Keskin and Nurhan Türker Tokan
Micromachines 2025, 16(9), 1030; https://doi.org/10.3390/mi16091030 - 8 Sep 2025
Viewed by 246
Abstract
This study presents a reconfigurable frequency-selective surface (R-FSS) designed to dynamically switch between WLAN, WiMAX, and sub-6 GHz band frequencies. The electronic switching mechanism of this R-FSS is controlled in real-time using PIN-diodes. Depending on the activation state of these diodes, the structure [...] Read more.
This study presents a reconfigurable frequency-selective surface (R-FSS) designed to dynamically switch between WLAN, WiMAX, and sub-6 GHz band frequencies. The electronic switching mechanism of this R-FSS is controlled in real-time using PIN-diodes. Depending on the activation state of these diodes, the structure operates in three distinct modes. Among the three modes, one exhibits polarization-stable wideband suppression, whereas the other two demonstrate polarization selectivity by interchanging between the dual-narrow and single-wide stopband regimes under orthogonal polarizations. The design is described with an equivalent-circuit model, corroborated by full-wave electromagnetic simulations, and validated through measurements of a fabricated prototype. This reconfigurability allows the proposed structure to operate across WLAN, sub-6 GHz, and WiMAX frequency ranges either with two narrow stopbands or with a single-wide stopband, while providing polarization selectivity for frequency-selective applications. Full article
(This article belongs to the Special Issue RF MEMS and Microsystems)
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24 pages, 11527 KB  
Article
Study on the Preparation of Diamond Film Substrates on AlN Ceramic and Their Performance in LED Packaging
by Shasha Wei, Yusheng Sui, Yunlong Shi, Junrong Chen, Tianlei Dong, Rongchuan Lin and Zheqiao Lin
Micromachines 2025, 16(9), 1029; https://doi.org/10.3390/mi16091029 - 8 Sep 2025
Viewed by 249
Abstract
Aluminum nitride (AlN) ceramic materials have relatively low thermal conductivity and poor heat dissipation performance, and are increasingly unsuitable for high-power LED packaging. In this study, diamond films were deposited on AlN ceramic substrates by microwave plasma chemical vapor deposition (MPCVD). The effects [...] Read more.
Aluminum nitride (AlN) ceramic materials have relatively low thermal conductivity and poor heat dissipation performance, and are increasingly unsuitable for high-power LED packaging. In this study, diamond films were deposited on AlN ceramic substrates by microwave plasma chemical vapor deposition (MPCVD). The effects of different process parameters on the crystal quality, surface morphology and crystal orientation of diamond films were studied, and the high thermal conductivity of diamond was used to enhance the heat dissipation ability of AlN ceramic substrates. Finally, the junction temperature and thermal resistance of LED devices packaged on AlN ceramic–diamond composite substrate, AlN ceramic substrate and aluminum substrate were tested. The experimental results show that compared with the traditional aluminum and AlN ceramic substrates, AlN ceramic–diamond composite substrates show excellent heat dissipation performance, especially under high-power conditions. Full article
(This article belongs to the Section D1: Semiconductor Devices)
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38 pages, 7252 KB  
Review
Advancements in Wearable Antenna Design: A Comprehensive Review of Materials, Fabrication Techniques, and Future Trends in Wireless Communication
by Zhikai Cao and Mai Lu
Micromachines 2025, 16(9), 1028; https://doi.org/10.3390/mi16091028 - 8 Sep 2025
Viewed by 326
Abstract
With the continuous development of wireless communication technology, the demand for wearable communication devices has rapidly increased. The antenna is one of the key components in communication devices, directly affecting the performance of wearable communication devices. As a result, wearable antenna design has [...] Read more.
With the continuous development of wireless communication technology, the demand for wearable communication devices has rapidly increased. The antenna is one of the key components in communication devices, directly affecting the performance of wearable communication devices. As a result, wearable antenna design has become a research hotspot in recent years. Wearable antennas are widely used in various fields of daily life, including healthcare, sports and entertainment, the internet of things (IoT), and military positioning. In the last decade, related researchers have studied wearable antennas from various perspectives, and this paper summarizes the design and fabrication of wearable antennas more comprehensively and systematically. This review covers material selection, manufacturing techniques, miniaturization technologies, and performance metrics, while addressing key design considerations. It also highlights recent research, applications in critical fields, and future development trends, offering valuable insights for the design and study of wearable antennas. Full article
(This article belongs to the Section E：Engineering and Technology)
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11 pages, 3178 KB  
Article
Effect of Bias Voltage on the Crystal Growth of AlN(002) Thin Films Fabricated by Reactive Magnetron Sputtering
by Yong Du, Haowen Zou, Tiejun Li and Guifang Shao
Micromachines 2025, 16(9), 1027; https://doi.org/10.3390/mi16091027 - 8 Sep 2025
Viewed by 416
Abstract
The study investigates the influence of bias voltage on the structural and morphological properties of aluminum nitride AlN (002) thin films deposited on sapphire substrates via reactive magnetron sputtering for high-frequency surface acoustic wave (SAW) devices. The results indicate that applying a positive [...] Read more.
The study investigates the influence of bias voltage on the structural and morphological properties of aluminum nitride AlN (002) thin films deposited on sapphire substrates via reactive magnetron sputtering for high-frequency surface acoustic wave (SAW) devices. The results indicate that applying a positive bias voltage (>0 V) yields AlN films with compact and uniform surfaces. As bias increases, the deposition rate initially rises before declining, while root–mean–square (RMS) roughness progressively decreases, reaching a minimum at 100 V, significantly enhancing surface quality. X-ray diffraction (XRD) analysis reveals enhanced (002) preferential orientation with increasing bias, indicating improved crystallinity. These findings demonstrate that optimized bias voltage not only refines surface morphology but also strengthens crystal alignment, particularly along the (002) plane, making AlN films highly suitable for high-frequency SAW applications, and provides data for the preparation of higher-quality AlN films. Full article
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22 pages, 4991 KB  
Review
Meta-Optics for Optical Engineering of Next-Generation AR/VR Near-Eye Displays
by Junoh Lee and Sun-Je Kim
Micromachines 2025, 16(9), 1026; https://doi.org/10.3390/mi16091026 - 7 Sep 2025
Viewed by 511
Abstract
Meta-optics, enabled by metasurfaces consisting of two-dimensional arrays of meta-atoms, offers ultrathin and multi-functional control over the vectorial wavefront of light at subwavelength scales. The unprecedented optical element technology is a promising candidate to overcome key limitations in augmented reality (AR) and virtual [...] Read more.
Meta-optics, enabled by metasurfaces consisting of two-dimensional arrays of meta-atoms, offers ultrathin and multi-functional control over the vectorial wavefront of light at subwavelength scales. The unprecedented optical element technology is a promising candidate to overcome key limitations in augmented reality (AR) and virtual reality (VR) near-eye displays particularly in achieving compact, eyeglass-type form factors with a wide field-of-view, a large eyebox, high resolution, high brightness, and reduced optical aberrations, at the same time. This review highlights key performance bottlenecks of AR/VR displays in the perspective of optical design, with an emphasis on their practical significance for advancing current technologies. We then examine how meta-optical elements are applied to VR and AR systems by introducing and analyzing the major milestone studies. In case of AR systems, particularly, two different categories, free-space and waveguide-based architectures, are introduced. For each category, we summarize studies using metasurfaces as lenses, combiners, or waveguide couplers. While meta-optics enables unprecedented miniaturization and functionality, it also faces several remaining challenges. The authors suggest potential technological directions to address such issues. By surveying recent progress and design strategies, this review provides a comprehensive perspective on the role of meta-optics in advancing the optical engineering of next-generation AR/VR near-eye displays. Full article
(This article belongs to the Special Issue Advances in Nanophotonics: Physics, Materials, and Applications)
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14 pages, 2389 KB  
Article
Neural Synaptic Simulation Based on ZnAlSnO Thin-Film Transistors
by Yang Zhao, Chao Wang, Laizhe Ku, Liang Guo, Xuefeng Chu, Fan Yang, Jieyang Wang, Chunlei Zhao, Yaodan Chi and Xiaotian Yang
Micromachines 2025, 16(9), 1025; https://doi.org/10.3390/mi16091025 - 7 Sep 2025
Viewed by 374
Abstract
In the era of artificial intelligence, neuromorphic devices that simulate brain functions have received increasingly widespread attention. In this paper, an artificial neural synapse device based on ZnAlSnO thin-film transistors was fabricated, and its electrical properties were tested: the current-switching ratio was 1.18 [...] Read more.
In the era of artificial intelligence, neuromorphic devices that simulate brain functions have received increasingly widespread attention. In this paper, an artificial neural synapse device based on ZnAlSnO thin-film transistors was fabricated, and its electrical properties were tested: the current-switching ratio was 1.18 × 107, the subthreshold oscillation was 1.48 V/decade, the mobility was 2.51 cm2V−1s−1, and the threshold voltage was −9.40 V. Stimulating artificial synaptic devices with optical signals has the advantages of fast response speed and good anti-interference ability. The basic biological synaptic characteristics of the devices were tested under 365 nm light stimulation, including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), short-term plasticity (STP), and long-term plasticity (LTP). This device shows good synaptic plasticity. In addition, by changing the gate voltage, the excitatory postsynaptic current of the device at different gate voltages was tested, two different logical operations of “AND” and “OR” were achieved, and the influence of different synaptic states on memory was simulated. This work verifies the application potential of the device in the integrated memory and computing architecture, which is of great significance for promoting the high-quality development of neuromorphic computing hardware. Full article
(This article belongs to the Special Issue Advanced Wide Bandgap Semiconductor Materials and Devices)
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16 pages, 1823 KB  
Article
Coupling and Preload Analysis of Piezoelectric Actuator and Nonlinear Stiffness Mechanism
by Wei Wang, Jinchuan Zheng, Zhe Sun and Xiaoqi Chen
Micromachines 2025, 16(9), 1024; https://doi.org/10.3390/mi16091024 - 6 Sep 2025
Viewed by 382
Abstract
This article presents a comprehensive investigation of the dynamic coupling between a piezoelectric actuator (PZT) and its driving nonlinear stiffness mechanism (NSM) stage for precise positioning control. Particular emphasis is placed on the preload-induced effects on the force transmission and structural separation between [...] Read more.
This article presents a comprehensive investigation of the dynamic coupling between a piezoelectric actuator (PZT) and its driving nonlinear stiffness mechanism (NSM) stage for precise positioning control. Particular emphasis is placed on the preload-induced effects on the force transmission and structural separation between the PZT and NSM. To ensure continuous mechanical contact between them, we propose a no-separation criterion based on acceleration matching, from which the minimum preload requirement is analytically derived. Additionally, static and dynamic simulations reveal that increasing the preload force from 0 N to 10 N can push the first natural frequency of the holistic system from 214.21 Hz to 258.17 Hz, respectively. This beneficially enhances the displacement consistency across different geometric configurations. Moreover, an appropriate preload force can prevent separation and increase system stiffness while reducing nonlinear deformation. Experimental results verifies that a preload of 10 N can prevent the separation between the PZT and NSM stage and maintain achievable output displacement of the stage within the range from 54.35μm to 129.42μm. This article offers the analytical results of preload setting to guarantee reliable actuation for nonlinear precision positioning stages. Full article
(This article belongs to the Special Issue Design and Real Time Implementation of Intelligent Control Schemes for Actuators)
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