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2023 International Congress on Ultrasonics, ICU Beijing 2023

作者： Zhang, Jikai Mu, Danyu Zhang, Zichao Jin, Hao Chen, Jinkai Xuan, Weipeng Dong, Shurong Luo, Jikui Zhejiang University Hangzhou310027 China Innovation and Research Institute of HIWING Technology Academy Beijing100074 China Zhejiang University Key Laboratory of Micro-nano Electronic Devices and Smart Systems of Zhejiang Province College of Information Science & Electronic Engineering Hangzhou310027 China Ministry of Education Key Laboratory of RF Circuits and Systems College of Electronics & Information Hangzhou Dianzi University Hangzhou310027 China Zhejiang University Key Laboratory of Collaborative sensing and autonomous unmanned systems of Zhejiang Province College of Information Science & Electronic Engineering Hangzhou310027 China

Surface acoustic wave (SAW) sensors based on Langasite (La3Ga5SiO14, LGS) have emerged as promising candidates for high-temperature strain measurement in passive wireless systems. However, limitations of strain transfer at temperatures above 800°C have hindered the repeatability of sensors due to temperature-induced effects. For instance, the aging of conventional high-temperature adhesives at elevated temperatures restricts the strain transfer between the measured object and the sensor. Moreover, materials like Inconel-600 exhibit a coefficient of thermal expansion significantly larger than the LGS, leading to thermal strains caused by thermal expansion mismatch beyond the maximum range of existing SAW strain sensors. Such factors increase the likelihood of sensor damage during a test. In this paper, we present a novel SAW sensor utilizing an ultra-thin LGS substrate encapsulated within a ceramic coating, which transfers strain by exerting pressure on both sides of the sensor. The strain sensor is mounted on an equal-strain beam inside a high-temperature furnace. The ceramic coating is not tightly bonded to the sensor, thereby mitigating the thermal expansion mismatch between the sensor and the beam at high temperatures. Furthermore, the ceramic coating can withstand large strain caused by thermal expansion while maintaining pressure on the sensor. This innovative SAW sensor enables repeat strain tests up to 800°C, including both calibration and formal tests. The measured strain exhibits an error of less than 5% compared to a standard strain gauge, demonstrating the sensor's enhanced performance and reliability. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Ceramic materials

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Rapid FSS Design Method Based on Fourier Transform

Rapid FSS Design Method Based on Fourier Transform

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Qiu, Huanran Han, Jiaqi Feng, Qiang Xi, Rui Li, Ying Chen, Hongsheng Zheng, Bin Li, Long Xidian University Hangzhou Institute of Technology Hangzhou311200 China Xidian University Key Laboratory of High-Speed Circuit Design EMC of Ministry of Education School of Electronic Engineering Xi'an710071 China The Electromagnetics Academy Zhejiang University Zhejiang University International Joint Innovation Center Haining314400 China Key Lab of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua China Institute of Zhejiang University Zhejiang University Jinhua321099 China Shaoxing Institute of Zhejiang University Zhejiang University Shaoxing312000 China

ISBN: (纸本)9798350375909

This article presents a rapid frequency selective surface (FSS) design method based on Fourier transform. The method aims to overcome the complexity and reduce the time consumption associated with the massive input simulation datasets in traditional design processes, providing an efficient and automated design solution. By introducing Fourier transform, the amount of simulation datasets can be significantly simplified, enhancing the speed and accuracy of neural network training. The method improves precision and speed in handling tasks with multiple parameters, offering an effective tool for fast FSS design. With the aid of neural network construction, users only need to input the desired simulation result curve, and the neural network model will quickly output optimal FSS structure parameters. This approach ensures design accuracy and stability while greatly increasing the efficiency of FSS design. © 2024 IEEE.

关键词： Neural network models

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Negative Conductivity Induced Reconfigurable Gain Metasurfaces and Their Nonlinearity

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Physical Review Letters 2024年第11期133卷 113801页

作者： Xiaoyue Zhu Chao Qian Erping Li Hongsheng Chen ZJU-UIUC Institute Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Science and Technology Innovation Center Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute of Zhejiang University

The past decades have witnessed the rapid development of metamaterials and metasurfaces. However, loss is still a challenging problem limiting numerous practical applications, including long-range wireless communications, superscattering, and non-Hermitian physics. Recently, great effort has been made to minimize the loss, however, they are too complicated for practical implementation and still restricted by the theoretical limit. Here, we propose and experimentally realize a tunable gain metasurface induced by negative conductivity, with deep theoretical analysis from scattering theory and equivalent circuits. In the experiment, we create metasurface samples embedded with tunable negative (or positive) conductivity to achieve adjustable gain (or loss). By varying the control bias voltages, the metasurfaces can reflect incident waves with additional controllable gain. Interestingly, we find the gain metasurfaces inherently pose nonlinearities, which are beneficial for nonlinear optics and microwave applications, particularly for the nonlinear activation of wave-based neural networks.

关键词： Electromagnetic waves & oscillations Gain properties of lasers Metamaterials Metasurfaces Nonlinear optics

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Extended-localized transition in diffusive quasicrystals

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Physical Review Applied 2024年第6期21卷 064035-064035页

作者： Zhoufei Liu Pei-Chao Cao Ying Li Jiping Huang Department of Physics State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Scientific and Technological Innovation Center International Joint Innovation Center Key Laboratory of Advanced Micro/Nano Electronic Devices and Smart Systems of Zhejiang The Electromagnetics Academy of Zhejiang University Shaoxing Institute of Zhejiang University

Compared with periodic systems, quasicrystals without translational invariance exhibit unexpected localization properties. The extended-localized transition in quasicrystals has been observed in both quantum and classical wave systems. However, its manifestation in diffusion systems, which serve as novel platforms for exploring phases of matter in condensed-matter physics, remains unexplored. Here we present an implementation of the extended-localized transition in a diffusive quasicrystal based on a coupled-ring chain structure. By modulating the thermal conductivities of the rings, we obtain the diffusive one-dimensional Aubry-André-Harper (AAH) model, which exhibits an extended-localized transition. Thanks to the ring-shaped chain, we clearly demonstrate the extended-localized transition under uniform excitation through temperature-field simulations. For the localized state, the temperature field clearly demonstrates a phenomenon of multiple localization centers, which has no counterpart in wave systems. We also quantitatively investigate the temperature evolution and size effect of this transition. Furthermore, local excitation is used to demonstrate the temperature field for both the extended state and the localized state. Besides, we implement the non-Hermitian diffusive AAH model by rotating the rings, whose temperature field shows a phenomenon of moving multiple localization centers in the localized phase. Finally, we give experimental suggestions for the diffusive AAH model and propose a potential application named the “double-trace distributed generator.” Our results should facilitate the design of flexible thermal devices and efficient heat management.

关键词： Anderson localization Diffusion Heat transfer Skin effect Thermoelectric effects Disordered systems Non-Hermitian systems Quasicrystals

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Design of Wideband Electromagnetic Absorbers Based on Deep Learning

Design of Wideband Electromagnetic Absorbers Based on Deep L...

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Robotics, Intelligent Control and Artificial Intelligence (RICAI), International Conference on

作者： Wan Ji Yan Li Erping Li Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province China Jiliang University Zhejiang China Key Laboratory of Advanced Micro-Nano Electronic Devices & Smart Systems and Applications Zhejiang University Zhejiang China

ISBN: (数字)9798331541699

ISBN: (纸本)9798331541705

This paper presents a deep learning-based multilayer perceptron (MLP) neural network approach for the design and optimization of electromagnetic absorbers operating in the 20-30 GHz frequency range. This method offers significant advantages in terms of miniaturization and wide bandwidth. By training the MLP neural network, the absorber structure is automatically optimized within this frequency band. The predicted results are in strong agreement with full-wave simulation outcomes. The findings demonstrate that this approach effectively enhances absorber efficiency, providing a novel solution for electromagnetic compatibility and stealth technology applications.

关键词： Deep learning Training Design methodology Multilayer perceptrons Electromagnetic absorbers Electromagnetic compatibility Structural engineering Electromagnetics Biological neural networks Wideband

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Design and Analysis of a Novel Miniaturized Ultra-Thin Wide-Band Metamaterial Absorber

Design and Analysis of a Novel Miniaturized Ultra-Thin Wide-...

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2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

作者： Ma, Jingnan Li, Yan Li, Erping School of Electronics and Information Engineering Hebei University of Technology Tianjin China China Jiliang University Key Lab. of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province China Zhejiang China Zhejiang University Key Laboratory of Advanced Micro-Nano Electronic Device and Smart Systems and Applications Zhejiang China

ISBN: (纸本)9781733509657

The volume of existing metamaterial absorber (MMA) is not small enough to be applied in miniaturized devices such as chip level. To solve this problem, a miniaturized ultrathin wide-band MMA is proposed in this paper. The thickness of proposed MMA is 1.1mm with a absorption rate of 99.6% at 19.7GHz. This paper also analyzes the influence of parameters of the proposed MMA on the absorption performance and proves that it has a certain tunability of the absorption band. By comparing with other works, the MMA proposed in this paper realizes the miniaturization of the structure while ensuring ultra-wideband. This benefit offers a novel approach to address the problem of difficult loading electromagnetic shielding structures in miniaturized chip designs. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Electromagnetic shielding

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Hybrid surface waves in twisted anisotropic heterometasurfaces

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Physical Review Applied 2024年第6期21卷 064034-064034页

作者： Xinyan Zhang Chenxu Bian Zheng Gong Ruoxi Chen Tony Low Hongsheng Chen Xiao Lin Interdisciplinary Center for Quantum Information State Key Laboratory of Extreme Photonics and Instrumentation International Joint Innovation Center The Electromagnetics Academy at Zhejiang University Department of Electrical and Computer Engineering Key Lab. of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang Jinhua Institute of Zhejiang University Shaoxing Institute of Zhejiang University

Recent advances in twisted photonic structures (e.g., twisted bilayer graphene and twisted anisotropic metasurfaces) have enabled many exotic phenomena of light-matter interactions, such as topological transition of the isofrequency contour of surface waves at the magic angle, photonic flatbands, and localization-to-delocalization transition of light. In general, the optical features of these twisted photonic structures are sensitive to the interlayer twist angle. Here we investigate the mode hybridization of surface waves supported by twisted bilayer anisotropic heterometasurfaces, whose two constituent metasurfaces are nonidentical and support surface waves with similar spatial confinements but distinct polarizations. Counterintuitively, we find that the shape of the isofrequency contour of these hybrid surface waves—eigenmodes with both transverse magnetic and transverse electric wave components—can be insensitive to the twist angle, due to the weak interlayer electromagnetic coupling. Moreover, the interlayer distance provides a unique route to reshape the dispersion of one specific kind of hybrid surface wave, while it has negligible influence on the other kinds. Our finding enriches the physics of light-matter interactions in twisted photonic structures and may open new possibilities to mold the flow of light at the subwavelength scale.

关键词： Classical optics Light-matter interaction Metamaterials Metasurfaces Near-field optics Photonics Plasmonics Van der Waals interaction

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Efficient evolution framework for chirality control in non-Hermitian systems with adiabaticity engineering

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Physical Review B 2024年第6期110卷 064308-064308页

作者： Dong Wang Wen-Xi Huang Bo Zhou Wenduo Yu Pei-Chao Cao Yu-Gui Peng Zheng-Yang Zhou Hongsheng Chen Xue-Feng Zhu Ying Li State Key Laboratory of Extreme Photonics and Instrumentation Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang International Joint Innovation Center The Electromagnetics Academy at Jinhua Institute of Zhejiang University Shaoxing Institute of Zhejiang University School of Physics and Innovation Institute Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of Physics

The eigenvalue of a non-Hermitian Hamiltonian often forms a self-intersecting Riemann surface, leading to a unique mode conversion phenomenon when the Hamiltonian evolves along certain loop paths around an exceptional point (EP). However, two fundamental problems exist with the conventional scheme of EP encircling: the speed of mode conversion is restricted by the adiabatic requirement, and the chirality cannot be freely controlled. Here, we introduce a method which dynamically engineers the adiabaticity in the evolution of non-Hermitian Hamiltonians that allows for both chiral and nonchiral mode conversion on the same path. Our method is based on quantifying and controlling the instantaneous adiabaticity, allowing for nonuniform evolution throughout the entire path. We apply our method into the microwave waveguide system and by optimizing the distributed adiabaticity along the evolution loop, we achieve the same quality of mode conversion as conventional quasiadiabatic evolution in only one-fourth of the time. Our approach provides an on-demand solution to address the speed and chirality challenges associated with EP encircling, which does not depend on specific model. It also facilitates the dynamic manipulation and regulation of nonadiabatic processes, thereby accelerating the operation and allowing for a selection among various mode conversion patterns.

关键词： Photonics Non-Hermitian systems PT-symmetry

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A Novel Miniaturized Dual-band Frequency Selective Surface 13

A Novel Miniaturized Dual-band Frequency Selective Surface

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13th Asia-Pacific International Symposium on Electromagnetic Compatibility and Technical Exhibition, APEMC 2022

作者： Xu, Shaojie Li, Yan Fang, Lidan Jin, Ning Sun, Zhe Yu, Heyuan Lei, Xiaoyong Huo, Shuyun Li, Erping Li, Bingheng China Jiliang University Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province Zhejiang China Hebei University of Technology College of Electronics & Information Engineering Tianjin China Key Laboratory of Advanced Micro-Nano Electronic Devices & Smart Systems and Applications Zhejiang China

ISBN: (数字)9781665416719

ISBN: (纸本)9781665416719

This paper presents a novel frequency selective surface (FSS) structure with miniaturized, low-frequency ratio. The proposed FSS is composed by cascading a curved cross ring and a double square ring (DSL)and is centrosymmetric. It exhibits the stable performance against the variation of the incident angles from 0° to 60° for both TE and TM polarizations. © 2022 IEEE.

关键词： Frequency selective surfaces

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Impact of the Interconnection Structure on RRAM-Based Crossbar Array in Neuromorphic Chip 13

Impact of the Interconnection Structure on RRAM-Based Crossb...

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13th Asia-Pacific International Symposium on Electromagnetic Compatibility and Technical Exhibition, APEMC 2022

作者： Fang, Lidan Li, Yan Xu, Shaojie Jin, Ning Yu, Heyuan Sun, Zhe Lei, Xiaoyong Huo, Shuyun Li, Erping Li, Bingheng China Jiliang University Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province Zhejiang China Hebei University of Technology College of Electronics & Information Engineering Tianjin China Key Laboratory of Advanced Micro-Nano Electronic Devices & Smart Systems and Applications Zhejiang China

ISBN: (数字)9781665416719

ISBN: (纸本)9781665416719

In this paper, the Izhikevich neuron model is used to simulate the spike signal, and a complete unit-cell equivalent circuit model of the RRAM-based crossbar array including parasitic effects is proposed. By changing the interconnection width, array size, and the RRAM resistance value, influences of the interconnection structure on the transmission characteristics of spike signals in the RRAM-based crossbar array for neuromorphic chips are analyzed. The simulation results show that the IR drop and crosstalk caused by the parasitic RLC components may be the main noise source that changes the operating voltage. Therefore, when the demand is met, the accuracy can be improved by changing the above-mentioned factors. © 2022 IEEE.

关键词： RRAM

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