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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Kong, Xianglin Zhao, Lei Wang, Fengjun Zhang, Shengjun Fu, Yixiang Pang, Xiaoyu Liu, Xiaochun Shen, Xiaopeng China University of Mining and Technology School of Information and Control Engineering XuZhou China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China Key Laboratory of Aeronautical Science and Technology for High Performance Electromagnetic Window Jinan China China University of Mining and Technology School of Materials and Physics Xuzhou China

ISBN: (纸本)9781665452366

An accuracy and efficient approach is proposed to fast design ultra-wideband microwave absorbers. The RC equivalent circuit model of absorbers is established according to impedance matching and transmission line theory. The model is suitable for low and high-frequency absorbers composed of multilayer square high impendence surface (HIS) and air layers of impendence matching. Absorbers with different parameters can be fast designed by utilizing the proposed model and genetic algorithm. The reflection coefficient of RC circuit and full-simulation are in good agreement, both of them are lower than -10 dB within 2-18 GHz or 4-50 GHz (fractional bandwidth of 160% or 170.37%), with the total thickness close to the Rozanov limit. An absorber is fabricated and measured to further verify the accuracy of the model. The measured results have a good agreement with the RC circuit model, which indicates the proposed method is an efficient way for fast designing ultra-broadband thin absorbers using double-layer (or multilayer) square HIS. © 2022 IEEE.

关键词： Multilayers

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Spiral Antenna Loaded with Directors for GPR Application 13

Spiral Antenna Loaded with Directors for GPR Application

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13th International Conference on Microwave and Millimeter Wave technology, ICMMT 2021

作者： Jiang, Zhiye Liu, Yaokun Liu, Shufang Shi, Xiaowei National Key Laboratory Of Science And Technology On Test Physics And Numerical Mathematics Beijing100076 China School Of Electronic Engineering Xidian University Xi'an710071 China

ISBN: (纸本)9781665434379

The antenna is one of the most critical components in the ground penetrating radar system. The spiral Antenna has the characteristics of ultra-wideband, circular polarization and small size, making it suitable for underground target detection. In this paper, a high-gain helical antenna is designed. Its |S11| is less than -10dB from 380MHz to 4GHz and the bandwidth is greater than 10:1, while a unidirectional radiation is achieved by embedding the antenna into a cylindrical cavity. At the same time, directors are loaded in the maximum radiation direction of the antenna to increase the gain of the antenna. The peak gain is 11.5dBi. The size of the antenna is 240mm×240mm×97mm. © 2021 IEEE.

关键词： Helical antennas

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Mechanically Beam-steering of Horn Antenna Using Non-uniform Flexible Meta-Surface 6

Mechanically Beam-steering of Horn Antenna Using Non-uniform...

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6th IEEE International Conference on Computer and Communications, ICCC 2020

作者： Jiang, Zhiye Zheng, Pei Qiu, Yuwei Zhu, Hailiang Ding, Chenyu Wei, Gao National Key Laboratory of Science and Technology on Test Physics Numerical Mathematics Beijing China School of Electronics and Information Northwestern Polytechnical University Xi'an Shaanxi China

ISBN: (纸本)9781728186351

Research on mechanically beam-steering of horn antenna using non-uniform meta-surface is presented in this paper. After optimizing the layout of quasi-I-shaped unit cell, we designed a flexible bi-layer meta-surface that can bring a main beam deflection of 40°. When the meta-surface is sliding along the long side of horn antenna, the main beam can be steered accordingly in a range of ±40°. A mechanically radiation reconfigurable antenna is thus achieved by a simple structure. Sliding of the meta-surface relative to the horn can be realized by a motor-driven conveyor belt when the prototype is fabricated in the following research. © 2020 IEEE.

关键词： Horn antennas

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Source-Configured Microwave Plasmonic Vortices Based on Single Meta-Particle

Source-Configured Microwave Plasmonic Vortices Based on Sing...

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

作者： Kong, Xianglin Zhao, Lei Shen, Xiaopeng Xu, Yinfang School of Information and Control Engineering China School of Materials Science and Physics China University Mining and Technology Xuzhou China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

ISBN: (纸本)9781733509657

In this paper, generation of plasmonic vortices with tunable topologic charges is proposed in the microwave regime. Tunable vortices with topologic charges of 0, +1 and -1 can be configured by illuminating incident plane waves with linearly polarization (LP), left-circularly polarization (LHCP) and right-circularly polarization (RHCP) on a single meta-particle, respectively. A spiral meta-particle operating at 2.94 GHz is designed, fabricated and measured to demonstrate the source-configured characteristics. The results showed that simulation and test are consistent with the theoretical ones. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Vortex flow

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Potential Predictability of Sea Surface Temperature in a Coupled Ocean-Atmosphere GCM

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Advances in Atmospheric sciences 2010年第4期27卷 921-936页

作者：严厉王盘兴俞永强李立娟王斌 Institute of Atmospheric Sciences Nanjing University of Information Science & Technology National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

Using the Flexible Global Ocean-Atmosphere-Land System model （FGOALS） version g1.11, a group of seasonal hindcasting experiments were carried out. In order to investigate the potential predictability of sea surface temperature （SST）, singular value decomposition （SVD） analyses were applied to extract dominant coupled modes between observed and predicated SST from the hindcasting experiments in this study. The fields discussed are sea surface temperature anomalies over the tropical Pacific basin （20~0S-20~0N, 120~0E- 80~0W）, respectively starting in four seasons from 1982 to 2005. On the basis of SVD analysis, the simulated pattern was replaced with the corresponding observed pattern to reconstruct SST anomaly fields to improve the ability of the simulation. The predictive skill, anomaly correlation coefficients （ACC）, after systematic error correction using the first five modes was regarded as potential predictability. Results showed that： 1） the statistical postprocessing approach was effective for systematic error correction; 2） model error sources mainly arose from mode 2 extracted from the SVD analysis-that is, during the transition phase of ENSO, the model encountered the spring predictability barrier; and 3） potential predictability （upper limits of predictability） could be high over most of the tropical Pacific basin, including the tropical western Pacific and an extra 10-degrees region of the mid and eastern Pacific.

关键词： coupled GCM hindcasting experiments SST singular value decomposition potential pre-dictability

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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05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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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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Research on networking communication technology based on small spacecraft 67

Research on networking communication technology based on sma...

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67th International Astronautical Congress, IAC 2016

作者： Peng, Qin Yang, Cao Lu, Gao Zhiye, Jiang Jinliang, Bai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics China Academy of Launch Vehicle Technology No. 1 Nan Da Hong Men Road Beijing China

Small spacecrafts have many advantages such as distribution area controllable, flexible, easy networking and co-optimal allocation of resources. The distributed collaborative networking technology can make several small spacecrafts to co-ordinate and work together as a whole. The technology has good prospects in the aerospace field and has obtained wide attention, for it can achieve communication transmission, space exploration, decision-making tasks and other functions. This paper proposes a collaborative networking solution based on small spacecraft, focusing on the research of key technologies such as networking method, communication protocols, synchronous communication and interference. This paper designed a collaborative network communication system solution, developed a prototype and verified the feasibility of the solution through simulation analysis and prototype testing. This paper also suggested the ideas and methods to improve future collaborative network communication system. Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved.

关键词： Spacecraft

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Unified OSTBC-based communication scheme for cooperative space vehicles

Unified OSTBC-based communication scheme for cooperative spa...

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IET International Radar Conference 2018, IRC 2018

作者： Geng, Jian Liu, Hongyan Jin, Wen Yan, Xinfeng Xu, Jin Beijing Institute of Space Long March Vehicle Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics China

In many spatial cooperative vehicle networks, omni-directional communication is preferred due to its flexibility for networking. In the recent studies, space time code was shown to be an effective approach for improving the performance of the omni-directional communication between space vehicles. This paper studies the unified scheme for the orthogonal space time block code-based transmission between two space vehicles equipped with different numbers of antennas. It is obtained that at most six passive antennas and four RF chains are enough for the typical use. In the proposed scheme, the receiver can perform a unified detection procedure regardless of the actual number of the transmit antennas, which facilitates the practical application. Simulation results validate the proposed scheme in terms of the cumulative distribution function of the received signal-to-noise ratios. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Space time codes

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Measurement and Analysis of Si3N4 Particles by Infrared Spectrum 3

Measurement and Analysis of Si3N4 Particles by Infrared Spec...

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3rd International Computing Imaging Conference, CITA 2023

作者： Wang, Xiaoli Li, Yanan Wei, Sai Li, Xinghua Yu, Han Aerospace Research Institute of Materials & Processing Technology Beijing China Beijing University of Technology Beijing China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

ISBN: (纸本)9781510671409

In this paper, the principle of Attenuated Total Reflection (ATR) is used to test and study the silicon nitride particle samples, and the influence of particle size, shape and crystal phase on its infrared spectral performance is emphatically analyzed. It is found that the larger the particle size of Si3N4 is, the more its extinction peak moves to the long wave. The smaller the particle size is, the lower the extreme value of infrared transmission in the characteristic spectrum segment is. For Si3N4 particles of the same scale, spherical like particles can obtain lower infrared transmittance, while cylindrical like ones show a wider range of infrared absorption bands. Under the same shape and similar scale, α Phase Si3N4 particles have better infrared absorption than β Phase. © 2023 SPIE.

关键词： Fourier transform infrared spectroscopy

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