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

作者： Zhu, Enze Li, Erji Wei, Zhun Yin, Wen-Yan Wang, Qian Innovative Institute of Electromagnetic Information and Electronic Integration Zhejiang University Key Lab of Advanced Micro/Nano Electronic Devices and Smart Systems of Zhejiang Province Hangzhou China Avic Research Institute for Special Structures of Aeronautical Composites Aeronautical Science Key Lab for High Performance Electromagnetic Windows Jinan China

ISBN: (纸本)9781733509657

In this paper, a fabrication-constrained conjugate adjoint gradient inverse design method (FCAG-IDM) is proposed to optimize the structural parameters of large-scale aperiodic frequency selective surfaces (FSSs). A characteristic of the proposed FCAG-IDM is that it constrains the optimized variables in each iteration considering the fabrication precision. The main advantage of FCAG-IDM is to achieve a fast inverse design for the scattering performance of electrically large-scale structure by combining fast forward simulator, conjugate adjoint gradient descent, and fabrication-constraint. The proposed FCAG-IDM is validated by both numerical and experimental results. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Fabrication

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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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Joint Analysis of Frequency-Selective Surfaces at Oblique Incidence in the Frequency, Angular, and Polarization Domains

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IEEE Transactions on Antennas and Propagation 2025年

作者： Xie, Jialong Li, Da Shen, Zhongxiang Li, Er-Ping Zhejiang University Key Laboratory of Advanced Micro/Nano Electronic Devices and Smart Systems and Applications College of Information Science and Electronic Engineering Hangzhou310027 China Beijing Institute of Technology Yangtze Delta Region Academy Zhejiang Jiaxing314019 China

This paper presents a comprehensive analysis of frequency-selective surfaces (FSSs) under oblique incidence, covering the frequency, angular, and polarization domains through their equivalent circuit models (ECM). The FSS structure is modeled as a microwave network, and its normalized impedance characteristics across these domains are systematically derived. The analysis addresses the conditions for perfect transmission, perfect reflection, and transmission bandwidth in the angular domain. To validate the proposed methodology, a dielectric slab with specifically tailored electrical and physical parameters is studied. Theoretical calculations and numerical simulations demonstrate diverse angular and frequency responses, including single-polarized single-pole filters, single-polarized multi-pole filters, double-polarized single-pole filters, and all-pass filters. Furthermore, detailed procedures for deriving the equivalent circuits and analyzing multilayer slabs, air layers, and metal-loaded structures are provided to extend the method’s applicability. A prototype slab is fabricated, and measured results show excellent agreement with theoretical predictions and numerical simulations, confirming the validity and effectiveness of the proposed approach. © 1963-2012 IEEE.

关键词： All-pass filters

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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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Four-Port SOLR Calibration Algorithm for Symmetric GSSG Probes

Four-Port SOLR Calibration Algorithm for Symmetric GSSG Prob...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Jiefeng Zhou Ling Zhang Da Li Junhui Chen Er-Ping Li College of Information Science and Electronic Engineering and The Zhejiang Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems and Applications Zhejiang University Hangzhou China

This paper proposes an efficient four-port short-open-load-reciprocity (SOLR) calibration algorithm for the symmetric Ground-Signal-Signal-Ground (GSSG) probes used for on-wafer S-parameter testing. This algorithm only needs four measurements, including one reciprocal Thru and three traditional calibration standards including Open, Short, and Load. Additionally, the exact S-parameters of the Thru are not mandatorily required. The correctness and effectiveness of the proposed algorithm is validated and corroborated by full-wave simulations up to 100 GHz.

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A Novel Miniaturized Zigzag Hexagonal Frequency Selective Surface

A Novel Miniaturized Zigzag Hexagonal Frequency Selective Su...

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IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP)

作者： Jialong Xie Xiaodong An Da Li Hanzhi Ma Er-Ping Li The Zhejiang Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems and Applications College of Information Science and Electronic Engineering Zhejiang University Hangzhou China

A novel miniaturized zigzag hexagonal frequency selective surface (FSS) element is proposed, where the structure has a dual-polarized angular stable passband. The FSS resonates at 4.0GHz, with a $3 \mathrm{~dB}$ passband spanning from 3.1 GHz to 4.72GHz, accommodating both transverse electric (TE) and transverse magnetic (TM) polarizations. Impressively, even at a 60° incidence angle, the shift in the transmission zero for the TE polarized wave is a mere 0.3%, demonstrating notable stability in terms of polarization and angular response.

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热扩散系统中非厄米趋肤效应的观测

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Science Bulletin 2024年第9期69卷 1228-1236页

作者：刘云开曹培超祁铭鸿黄强开来高峰彭玉桂李鹰祝雪丰 School of Physics and Innovation Institute Huazhong University of Science and TechnologyWuhan 430074China State Key Laboratory of Extreme Photonics and Instrumentation ZJU-Hangzhou Global Scientiﬁc and Technological Innovation CenterZhejiang UniversityHangzhou 310027China International Joint Innovation Center The Electromagnetics Academy at Zhejiang UniversityZhejiang UniversityHaining 314400China Key Lab.of Advanced Micro/Nano Electronic Devices&Smart Systems of Zhejiang Jinhua Institute of Zhejiang UniversityZhejiang UniversityJinhua 321099China Shaoxing Institute of Zhejiang University Zhejiang UniversityShaoxing 312000China

The paradigm shift of Hermitian systems into the non-Hermitian regime profoundly modifies inherent property of the topological systems, leading to various unprecedented effects such as the nonHermitian skin effect(NHSE). In the past decade, the NHSE has been demonstrated in quantum, optical and acoustic systems. Beside those wave systems, the NHSE in diffusive systems has not yet been observed, despite recent abundant advances in the study of topological thermal diffusion. In this work,we design a thermal diffusion lattice based on a modified Su-Schrieffer-Heeger model and demonstrate the diffusive NHSE. In the proposed model, the asymmetric temperature field coupling inside each unit cell can be judiciously realized by appropriate configurations of structural parameters. We find that the temperature fields trend to concentrate toward the target boundary which is robust against initial excitation conditions. We thus experimentally demonstrated the NHSE in thermal diffusion and verified its robustness against various defects. Our work provides a platform for exploration of non-Hermitian physics in the diffusive systems, which has important applications in efficient heat collection, highly sensitive thermal sensing and others.

关键词： Non-Hermitian skin effect Asymmetric coupling Thermal metamaterial Heat diffusion

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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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The application value of H-reflex induced by electrical stimulation of the sacral nerve at the S3 foramen in stimulus parameter programming

The application value of H-reflex induced by electrical stim...

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2024 International Conference on Next Generation electronics and Photonics, INGEP 2024

作者： Min, Yu Jiang, Haofei Jin, Hao Yu, Yanlan Ding, Guoqing Jiang, Haihong College of Information Science and Electronic Engineering Zhejiang University Hangzhou China The First Clinical Medical School of Wenzhou Medical University School of Information and Engineering Wenzhou Medical University Wenzhou China Key Lab. of Advanced Micro/Nano Electronic Devices and Smart Systems of Zhejiang Hangzhou China Sir Run Run Shaw Hospital Zhejiang University School of Medicine Hangzhou China

Although manufacturers of sacral nerve stimulators and related research have provided many guiding opinions on the programming values of stimulation parameters, the stimulation parameters used for long-term treatment of patients are still largely influenced by the experience of doctors and the subjective feelings of patients. We found a high positive correlation between the appearance and amplitude growth trend of the H-reflex induced by S3 nerve root stimulation, the stimulation amplitude corresponding to the inflection point, and the subjective sensation threshold and pain threshold of patients who underwent the first phase of implantable stimulatory surgery, through electromyography collection. Based on this, we believe that the information on the H-reflex triggered by S3 nerve root stimulation will provide a more intuitive and quantifiable non-invasive way for doctors to assist in determining the appropriate stimulator amplitude for long-term treatment of patients. This will help reduce unnecessary pain and potential permanent nerve damage risks that may occur to patients during parameter programming and debugging processes. Especially when facing patients with communication barriers or lack of cooperation, it is more meaningful. © Published under licence by IOP Publishing Ltd.

关键词： Electromyography

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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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