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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Xun Luo Li Liu Xin Liu National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China China Academy of Launch Vehicle Technology Beijing China

A new method of aircraft low altitude penetration is proposed with temporal constraints that allow periods of high observability interspersed with periods of low observability. The aircraft’s RCS character is simplified into the “bow-tie” distribution, then the aircraft can dynamically adjust its yaw angle to minimize the risk from the radars. According to the modified Lock Loss model and the TWS(Track While Scan) radar work flow, and real-time evaluating model on the original path, a fast real-time path planning method is present on the situation that unexpected threats occur. An example of real-time path planning is given.

关键词： Radar cross-sections Atmospheric modeling Heuristic algorithms Airborne radar Real-time systems Path planning Safety

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1-bit Coding Metasurface for Wideband RCS Reduction

1-bit Coding Metasurface for Wideband RCS Reduction

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yinfang Xu Jiaqi Liu Lu Gao Xia Ai Zhongjie Zhang Huan Liang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

This paper achieve efficient RCS reduction over a wide frequency range by exploiting the reflection properties of the coding metasurface. The metasurface consists of “0” cells and “1” cells, and the reflection phase difference is close to 180° over a wide frequency range. By designing the spatial random coding arrangement of “0” units and “1” units, the electromagnetic waves incident on the metasurface form diffuse reflection, so as to achieve the purpose of broadband RCS reduction. The simulation results show that when the incident wave is irradiated vertically, the metasurface can basically achieve a RCS reduction of more than 10dB in a wide frequency band of 10-20.5GHz compared to a metal plate of the same size. In the case of oblique incidence, the RCS reduction still has a good effect, which is basically the same as the curve at normal incidence, and has the characteristics of wide-angle incidence RCS reduction. The reduced bandwidth of the broadband RCS of the coding metasurface is basically consistent with the 10 dB polarization bandwidth of the cell structure. The design of the metasurface is simple and efficient, so it has great application potential in stealth new technologies and new materials.

关键词： Electric potential Simulation Electromagnetic scattering Metals Metasurfaces Computational electromagnetics Reflection

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Ballistic Target Micro-motion Parameters Identification with CNN Denoiser Based on Deep Learning

Ballistic Target Micro-motion Parameters Identification with...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Ruixin Lai Xia Ai Shaoran Wang Mengmeng Li Jiaqi Liu Dazhi Ding School of Electronics and Optical Engineering Nanjing university of science and technology Nanjing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

This paper proposes a method to identify micromotion parameters of radar echo with noise based on deep learning. The radar echo database is constructed from the point scattering model and the micro-Doppler spectrogram dataset is obtained then. The convolutional neural network is constructed to denoise radar echo with three kind of noises with different SNR, and target micro-motion parameters are identified.

关键词： Deep learning Parameter estimation Noise reduction Scattering Radar Speckle Radar scattering

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A New One-Dimensional Photonic Crystals for Infrared Emission Modulation

A New One-Dimensional Photonic Crystals for Infrared Emissio...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yuning Zhang Shengjun Zhang Hang Song Yichun Cui Jiaqi Liu Lihong Ai National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Capital Aerospace Machinery Corporation Limited Beijing China

With the wide application of infrared detection in the military field, the problem of how to reduce the probability of military targets being detected and identified has become urgent. In this paper, one-dimensional photonic crystals with wide incidence angle range are analyzed and simulated. The reflectance and transmittance properties of different structures are discussed with application in modulation of infrared emission.

关键词： Reflectivity Simulation Modulation Photonic crystals Germanium Computational electromagnetics Stability analysis

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Study on 2D Plasma Photonic Crystals with Defect Modes Using FDTD Method

Study on 2D Plasma Photonic Crystals with Defect Modes Using...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Hang Song Yuning Zhang Jiaqi Liu Lihong Ai Shengiun Zhang National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Captial Aerospace Machinery Coporation Limited Beijing China

In this paper, a typical uniform unmagnetized two-dimensional plasma photonic crystal with a single linear defect mode is simulated based on the finite difference time domain method, and the effects of defect mode position and size on its photonic band gaps characteristics are explored respectively. the research can provide an idea for tuning the electromagnetic properties of two-dimensional plasma photonic crystals.

关键词： Plasma properties Time-frequency analysis Photonic band gap Two dimensional displays Plasmas Time-domain analysis Electromagnetics

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Piecewise Linear Recursive Convolution Method Applied in One-dimensional Unmagnetized Plasma

Piecewise Linear Recursive Convolution Method Applied in One...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Jiaqi Liu Gang Meng Lei Mu Lu Gao Jinjun Mo Runhui Wu Weidong Wang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China School of Information and Communication Guilin University of Electronic Technology Guilin China

The piecewise linear recursive convolution(PLRC) method based on finite difference time domain(FDTD) is used to calculate the reflection and transmission characteristics of electromagnetic waves from one-dimensional unmagnetized plasma. The results are shown that this method has obvious advantages in accurately calculating the electromagnetic problems of one-dimensional, small-scale and thin-layer dielectric materials.

关键词： Convolution Electromagnetic scattering Dielectric materials Computational electromagnetics Reflection Plasmas Electromagnetics

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A Radiation Pattern-Reconfigurable Patch Antenna with Tunable CSRR based on Liquid Metal and 3-D Printed Microfluidics

A Radiation Pattern-Reconfigurable Patch Antenna with Tunabl...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yumeng Wang Lu Gao Pei Zheng Lingnan Song School of Electronic and Information Engineering Beihang University Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

In this article, a radiation patternreconfigurable patch antenna with tunable complementary split-ring resonators (CSRR) based on liquid metal (LM) and 3-D printed microfluidics is presented. The antenna is composed of three layers, a top coaxial fed rectangular patch, a middle ground plane with two CSRRs etched symmetrically, and two bottom microfluidics channels each adhered underneath the corresponding CSRR. Pattern reconfiguration is achieved by filling the microfluidic channels with the liquid metal plugs to change the physical parameters of the CSRR structure. By adjusting the length of the slot stubs in CSRRs, the main beam of the double CSRR-loaded antenna can be continuously scanned from -46° to 46° in elevation plane.

关键词： Liquids Slot antennas Patch antennas Simulation Metals Filling Resonators

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Rapid Prediction Model of Equivalent Thermal Conductivity of Plain Weave Fabric in Space Environment

SSRN

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SSRN 2023年

作者： Qin, Jiaxing Wu, Jiawen Mu, Lei Zhang, Biao Li, Jian Xu, Chuanlong National Engineering Research Center of Power Generation Control and Safety School of Energy and Environment Southeast University Nanjing210096 China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China

The prediction of effective thermal conductivity of aerospace insulation materials is crucial for insulation design and radiation characteristics control of space targets. In this paper, a rapid and accurate prediction model is proposed for the effective thermal conductivity of plain weave fabrics in space environments. This model assumes that the cross-sectional shape and bending degree of yarns within aerospace fabrics remain unchanged. To represent the structural characteristics of the plain weave fabric, a dimensionless parameter called "[[EQUATION]]" is defined. numerical simulations are conducted to investigate the effects of fabric structure, temperature, and yarn thermal properties on the effective thermal conductivity of multilayer fabrics. Three parameters are identified as the most influential factors for the effective thermal conductivity of plain weave fabrics: the structural parameter [[EQUATION]], and the axial and radial thermal conductivities of yarns. Based on extensive simulation data, an empirical formula is proposed for the rapid prediction of the effective thermal conductivity of plain weave fabrics. Moreover, polyester, cotton, and wool plain weave fabric samples are tested for their thermal conductivity in a vacuum environment. The predicted results from the empirical formula proposed in this study exhibit a deviation of less than 6% when compared to experimental measurements. This study can provide valuable insights for the design of plain weave fabrics used in aerospace insulation materials. © 2023, The Authors. All rights reserved.

关键词： Yarn

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UAV Track Planning Algorithm Based on Graph Attention Network and Deep Q Network 11th

UAV Track Planning Algorithm Based on Graph Attention Networ...

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11th International Conference on Image and Graphics, ICIG 2021

作者： Hu, Xinyu Gao, Jingpeng Jiang, Zhiye College of Information and Communication Engineering Harbin Engineering University Harbin China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9783030873578

To solve the problem that the deviation of the Unmanned Aerial Vehicle (UAV) flight status data collected by the equipment during flight leads to the failure of the mission, this paper proposes a UAV track planning algorithm based on Graph Attention Network and Deep Q Network (DQN). Firstly, we use the camera to collect images and apply pre-trained ResNet to extract image features. Secondly, we adopt the Graph Attention Network to establish the connection between the sensor-measured flight state information and the actual flight state information. Thirdly, we build the optimization model of flight state. Moreover, based on the Deep Reinforcement Learning (DRL) theory, the DQN-based UAV track planning system is trained. Finally, the system combined the optimized flight state to complete the optimal flight action output to realize the track planning. Simulation results show that, compared with the original algorithm which is under the same flight conditions as the proposed algorithm, the velocity deviation rate of the proposed algorithm is improved by 46.79%, which can plan a high-quality track and has good engineering application value. © 2021, Springer Nature Switzerland AG.

关键词： Image processing

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On the metric resolvent: nonexpansiveness, convergence rates and applications

arXiv

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arXiv 2021年

作者： Xue, Feng National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

In this paper, we study the nonexpansive properties of metric resolvent, and present a convergence rate analysis for the associated fixed-point iterations (Banach-Picard and Krasnosel’skii-Mann types). Equipped with a variable metric, we develop the global ergodic and non-ergodic iteration-complexity bounds in terms of both solution distance and objective value. A byproduct of our expositions also extends the proximity operator and Moreau’s decomposition identity to arbitrary variable metric. It is further shown that many classes of the first-order operator splitting algorithms, including alternating direction methods of multipliers, primal-dual hybrid gradient and Bregman iterations, can be expressed by the fixed-point iterations of a simple metric resolvent, and thus, the convergence can be analyzed within this unified *** Codes 68Q25, 47H05, 90C25, 47H09 Copyright © 2021, The Authors. All rights reserved.

关键词： Iterative methods

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