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2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio science Meeting, AP-S/URSI 2022

作者： Liu, Ganyu Zhu, Hailiang Wang, Kai Qiu, Yuwei Mou, Jinchao Zheng, Pei Wei, Gao Northwestern Polytechnical University Shaanxi Xi'an710129 China The Beijing Research Institute of Telemetry Beijing100094 China The National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (数字)9781665496582

ISBN: (纸本)9781665496582

A new ultra-wideband magnetoelectric (ME) dipole antenna is proposed as a dual-polarized base station antenna for 3G, LTE and Sub-6GHz 5G wireless networks. Double layers of ME dipoles with different sizes are combined to expand the bandwidth, and the orthogonal placement of ME dipoles enables dual polarization radiation. Simulation results reveal that the proposed base station antenna achieves 133.3% fractional bandwidth and satisfying radiation characteristics, including high front-to-back ratio (FBR) (>14 dB), high cross-polarization levels (>20 dB), and stable gains about 5-10 dBi in 1-5GHz. © 2022 IEEE.

关键词： Polarization

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A Novel Tunable FSS of miniaturized unit cell for lower frequency

A Novel Tunable FSS of miniaturized unit cell for lower freq...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yichun Cui Shengjun Zhang Mingliang Wang Jiaqi Liu Xin Liu Yue Wang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

Large working bandwidth is now an attractive topic for FSS design, while it's hard to acquire a FSS structure with very wide bandwidth. So the way to actively tune the response frequency of the FSS, thus giving dynamic wide bandwidth maybe an available solution to this problem. In this paper, a two-layer structure loaded with variable capacitor was proposed to adjust resonance frequency. The upper layer employs strip lines and the lower layer joins capacitors between the cross rings to tune the frequency response curves of the whole structure quantitatively. This active frequency selective surface (AFSS) is sensitive to the change of loaded capacitance in some range while stay invariably above that, in which element can be regarded as being connected. Simulation results indicates that the rationality of analysis, which provides a general method to adjust resonance frequency and guides the active design of corresponding passive FSS in return.

关键词： Frequency selective surfaces Resonant frequency Capacitance Capacitors Equivalent circuits Integrated circuit modeling Bandwidth

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Individual Identification Algorithm of Known Emitters Based on Lightweight Binary Channels Neural Network 12

Individual Identification Algorithm of Known Emitters Based ...

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12th International Conference on Information technology in Medicine and Education, ITME 2022

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

ISBN: (纸本)9798350310153

Aiming at the problem that the traditional specific emitter identification method has poor feature extraction ability and limited recognition effect, this paper proposes a known specific emitter identification algorithm based on the LBCNet (the Lightweight Binary Channels Net). The algorithm uses bispectrum and cyclic spectrum to highlight the unintentional information in the pulse. Then, it combines the idea of depthwise separable convolution to design the LBCNet to realize adaptive feature extraction, fusion, and classification. Finally, it integrates the attention mechanism to highlight the effective information of the image, enhance the neural network's learning ability and improve the identification performance of specific emitters. The simulation results show that the recognition rate of the proposed algorithm is as high as 94.53% at 0dB, which has good engineering practical value and can be applied to the field of electronic reconnaissance. © 2022 IEEE.

关键词： Convolution

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Modulation recognition of emitter signals based on SDAE-ODCNN 5

Modulation recognition of emitter signals based on SDAE-ODCN...

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IET International Radar Conference 2020, IET IRC 2020

作者： Wang, Xu Gao, Jingpeng Gao, Lu Wang, Fu 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)9781839535635

In order to improve the recognition rate of emitter signals modulation under low signal noise ratio (SNR), an end-to-end method based on the stacked denoising autoencoder (SDAE) - one dimensional convolutional neural network (ODCNN) is proposed in this paper. The SADE-ODCNN is designed in this method and trained through a two-step training. In the SDAE-ODCNN model, the encoder of the SDAE can extract the denoised and compressed features of the received emitter signals. Then the ODCNN can further extract features to realize the recognition. The simulation results show that the average recognition rate of the method can reach 0.94 under 0dB. Thus the proposed method has a good application in the field of emitter signals modulation recognition. © 2020 Institution of Engineering and technology. All rights reserved.

关键词： Modulation

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Ellipse Fitting Based on Neural Network Optimization 41

Ellipse Fitting Based on Neural Network Optimization

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第41届中国控制会议

作者： Chenrong Long Peng Liu Qinglei Hu School of Automation Science and Electrical Engineering Beihang University National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing Institute of Space Long March Vehicle School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China.

ISBN: (数字)9789887581536

ISBN: (纸本)9781665482561

Ellipse fitting is to estimate the parameters of the ellipse from a set of coplanar points,but the geometric distance from the plane point to the elliptic curve is difficult to calculate *** paper proposes a neural network optimization-based algorithm to estimate the geometric distances from plane points to elliptic curves to solve the ellipse fitting ***,the neural network is firstly applied to train the geometric distance between the plane point and the standard ellipse,and then obtain the geometric distance between the plane point and the general ellipse through the rotation and translation ***,use minimizing the sum of the Euclidean distances from the plane point to the elliptic curve as the objective function,and finally use the gradient descent method to iteratively solve the ellipse ***,the proposed method avoids the direct algebraic solution of the geometric distance from the plane point to the elliptic curve and the performance of the algorithm to gether with its robustness to noise are analysed via numerical simulation.

关键词： Ellipse Fitting Coplanar Points Geometric Distance Neural Network Optimization

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A Dual-Band Multilayer Heterogeneous Frequency Selective Surface with Miniaturized Unit Cell

A Dual-Band Multilayer Heterogeneous Frequency Selective Sur...

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2018 IEEE International Conference on Computational Electromagnetics, ICCEM 2018

作者： Cui, Yichun Zhang, Shengjun Liu, Jiaqi Liu, Xin Xue, Hui Zhang, Borong National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China Beijing Institute of System Engineering Beijing China Beijing Institute of Astronauctical Systems Engineering Beijing100076 China

ISBN: (纸本)9781538612415

In terms that most researches about Frequency Selective Surface (FSS) concentrate on single layer structure design or FSS with one fundamental mode, a multilayer heterogeneous dual-band frequency selective surface composed of slot FSS, dielectric medium, patch FSS is proposed. This FSS possess miniaturized unit cell with dimension of 6× 6mm2, it acts as a dual-band filter in given bands while behaving as an entire reflector in others. Results show that this dual-band frequency selective surface has narrow transmission bandwidths near 8.5GHz and 19.5GHz and flat rejection bands except for that. The structure exhibits excellent stability for oblique incident angles and provides polarization-independent response with compact design which moves the operating bands away from grating lobes. A method to adjust the element's size is proposed as well based on basic elements when given pass band frequency changed. © 2018 IEEE.

关键词： Frequency selective surfaces

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The Role of Regional Ocean–Atmosphere Coupling in Simulating the2020 Extreme Mei-yu Event

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Advances in Atmospheric sciences 2025年第5期 904-920页

作者： Kai LI Liwei ZOU Li DAN Hui ZHENG Zhongfeng XU Jianping TANG Fuqiang YANG Wenli FEI Taotao ZHANG Chunxiang SHI Zong-Liang YANG Key Laboratory of Regional Climate and Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences Key Laboratory of Meteorological Disaster (KLME) Ministry of Education & Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD) Nanjing University of Information Science & Technology State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences School of Atmospheric Sciences Nanjing University Institute of Applied Ecology Chinese Academy of Sciences National Meteorological Information Center China Meteorological Administration Department of Earth and Planetary Sciences Jackson School of GeosciencesThe University of Texas at Austin

The Yangtze–Huaihe River Valley(YHRV) experienced a record-breaking mei-yu season during the summer of 2020,prompting investigation into the role of regional ocean–atmosphere coupling in simulating this extreme event. Through comparative analysis of regional ocean–atmosphere coupled(CP) and atmosphere-only(WRF) simulations, the aim of this study was to elucidate the mechanisms underlying this phenomenon. Results indicate that CP effectively reproduced the observed sea surface temperature spatial distribution and its daily variation during the period from 25 June to 25 July 2020,and notably reduced the wet biases over the YHRV when compared to WRF simulations. This improvement in representation was manifested in the observed rainfall spatial distribution and daily variability. The wet biases simulated by WRF were associated with a stronger 200-h Pa westerly jet and a more westward-positioned western North Pacific subtropical high(WNPSH) with more intense 500-h Pa winds and a stronger 850-h Pa circulation. However, these biases were significantly reduced in CP simulations. Mechanism analysis revealed that regional ocean–atmosphere coupling over the western Northwest Pacific influenced surface turbulent heat fluxes and atmospheric instability, thereby modulating the intensity and position of the WNPSH and associated circulation subsystems at different levels. Moreover, adjustments in land–sea thermal contrast induced by ocean–atmosphere coupling impacted YHRV precipitation by altering East Asian circulation systems. These findings highlight the significant role of regional ocean–atmosphere coupling in enhancing the simulation and understanding of extreme mei-yu events over East Asia.

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Design of W-band Sheet Beam EIK

Design of W-band Sheet Beam EIK

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Asia-Pacific Conference on Microwave

作者： Shuyuan Chen Jinliang Bai Ran Zhang Pei Zheng Jiaqi Liu Xin Liu Hongyan Liu Lu Gao National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (数字)9781728135175

ISBN: (纸本)9781728135182

Microwave tube is a vacuum electron device which can be used for amplification in the microwave frequency range. Sheet beam Extended Interaction Klystron (EIK) is an attractive Millimeter Waves amplifier because of its compact configuration, small voltage and high gain per unit length. In this paper, RF structure and the whole tube for W-band sheet beam EIK has been designed. A new and effective method of designing and studying W-band sheet beam EIK is presented in this paper. In order to get the same output power, several kinds of W-band sheet beam EIK are designed and compared. By optimizing the position of cavities, the output power can achieve 30 kW, which is calculated by threedimensional particle in cell (3D-PIC) software. It is a powerful basis for the subsequent study of sheet beam EIK.

关键词： Power generation Klystrons Power amplifiers physics mathematics Urban areas

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Near-field Measurement Method for Electromagnetic Scattering of Electrically Large-scale Plasma

Near-field Measurement Method for Electromagnetic Scattering...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Jiaqi Liu Lu Gao Runhui Wu Xia Ai Song Chai Xin Liu Shengjun Zhang Yichun Cui National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

In the near-field test environment of 01500×3300mm vacuum vessel with low electromagnetic scattering, the relative measurement method is used, that is, the results of electrically large-scale plasma radar cross s... 详细信息

关键词： Radar cross-sections Volume measurement Standards organizations Electromagnetic scattering Elementary particle vacuum Energy measurement Plasma measurements

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An Updated Estimation of Radiative Forcing due to CO_2 and Its Effect on Global Surface Temperature Change

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Advances in Atmospheric sciences 2013年第4期30卷 1017-1024页

作者：张华张若玉石广玉 Laboratory for Climate Studies China Meteorological Administration National Climate Center Atmosphere Science Academy Nanjing University of Information Science and Technology State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics

New estimations of radiative forcing due to CO2 were calculated using updated concentration data of CO2 and a high-resolution radiative transfer model. The stratospheric adjusted radiative forcing （ARF） due to CO2 from the year 1750 to the updated year of 2010 was found to have increased to 1.95 W m-2, which was 17% larger than that of the IPCC＇s 4th Assessment Report because of the rapid increase in CO2 concentrations since 2005. A new formula is proposed to accurately describe the relationship between the ARF of CO2 and its concentration. Furthermore, according to the relationship between the ARF and surface temperature change, possible changes in equilibrium surface temperature were estimated under the scenarios that the concentration of CO2 increases to 1.5, 2, 2.5, 3, 3.5 and 4 times that of the concentration in the year 2008. The result was values of ＋2.2℃, ＋3.8℃, ＋5.1℃, ＋6.2℃, ＋7.1℃ and ＋8.0℃ respectively, based on a middle-level climate sensitivity parameter of 0.8 K （W m 3）-1. Non-equilibrium surface temperature changes over the next 500 years were also calculated under two kinds of emission scenarios （pulsed and sustained emissions） as a comparison, according to the Absolute Global Temperature change Potential （AGTP） of CO2. Results showed that CO2 will likely continue to contribute to global warming if no emission controls are imposed, and the effect on the Earth-atmosphere system will be difficult to restore to its original level.

关键词： CO2 radiative forcing surface temperature change Global Temperature change Potential

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