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Propagation characteristics of microwaves in dusty plasmas with multi-collisions

Plasma Science and technology 2017年第5期19卷 6-14页

作者：洪运海袁承勋贾洁姝高瑞林王莹周忠祥王晓鸥李辉吴建 Department of Physics Harbin Institute of Technology National Key Laboratory of Electromagnetic Environment China Research Institute of Radio Wave Propagation

In this study, we consider three main collisions in dusty plasmas and investigate the effects of dust grains on the propagation of electromagnetic（EM） waves through uniform, unmagnetized and weakly ionized dusty plasma. The Drude model is improved to describe the dielectric property of dusty plasmas, which accounts for collisions including electron–molecule, electron–ion, and electron–dust particles. Based on the improved Drude model, the propagation characteristics of microwaves in dusty plasmas have been numerically calculated and *** results show that the propagation characteristics of microwaves through dusty plasmas are different from those through normal plasmas. The effects of dust density and size are mainly studied. Numerical results indicate that the momentum transfer between electrons and dust grains makes more energy loss. The dust density and dust size have a similar influence on EM wave propagation, resulting in less transmission and more absorption.

关键词： dusty plasmas electromagnetic waves Drude model

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Reconstruction of sub cross-correlation cancellation technique for unambiguous acquisition of BOC(kn, n) signals

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Journal of Systems Engineering and Electronics 2019年第5期30卷 852-860页

作者： JI Yuanfa CHEN Xiaoqian FU Qiang SUN Xiyan ZHEN Weimin Guangxi Key Laboratory of Precision Navigation Technology and Application Guilin University of Electronic TechnologyGuilin 541004China National&Local Joint Engineering Research Center of Satellite Navigation Positioning and Location Service Guilin 541004China Key Laboratory of Radio Wave Environment and Modeling Technology Qingdao 266000China

In order to solve the problem of ambiguous acquisition of BOC signals caused by its property of multiple peaks,an unambiguous acquisition algorithm named reconstruction of sub cross-correlation cancellation technique(RSCCT)for BOC(kn,n)signals is *** this paper,the principle of signal decomposition is combined with the traditional acquisition algorithm structure,and then based on the method of reconstructing the correlation *** method firstly gets the sub-pseudorandom noise(PRN)code by decomposing the local PRN code,then uses BOC(kn,n)and the sub-PRN code cross-correlation to get the sub cross-correlation ***,the correlation peak with a single peak is obtained by reconstructing the sub cross-correlation function so that the ambiguities of BOC acquisition are *** simulation shows that RSCCT can completely eliminate the side peaks of BOC(kn,n)group signals while maintaining the narrow correlation of BOC,and its computational complexity is equivalent to sub carrier phase cancellation(SCPC)and autocorrelation side-peak cancellation technique(ASPeCT),and it reduces the computational complexity relative to *** BOC(n,n),the acquisition sensitivity of RSCCT is 3.25 dB,0.81 dB and 0.25 dB higher than binary phase shift keying(BPSK)-like,SCPC and ASPeCT at the acquisition probability of 90%,*** peak to average power ratio is 1.91,3.0 and 3.7 times higher than ASPeCT,SCPC and BPSK-like at SNR=–20 dB,*** BOC(2n,n),the acquisition sensitivity of RSCCT is 5.5 dB,1.25 dB and 2.69 dB higher than BPSK-like,SCPC and ASPeCT at the acquisition probability of 90%,*** peak to average power ratio is 1.02,1.68 and 2.12 times higher than ASPeCT,SCPC and BPSK-like at SNR=–20 dB,respectively.

关键词： signal decomposition sub cross-correlation reconstructingcorrelation function acquisition performance

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Machine-learning based ocean atmospheric duct forecasting:a hybrid model-data-driven approach

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The Journal of China Universities of Posts and Telecommunications 2023年第4期30卷 1-9页

作者： Feng Yuting Gong Haobing Hao Xiaojing Gao Hui Guo Xiangming Key Laboratory of Trustworthy Distributed Computing and Service Beijing University of Posts and TelecommunicationsBeijing 100876China Key Laboratory of Radio Wave Propagation Characteristics and Modeling Technology 22nd Research Institute of China Electronics Technology CorporationQingdao 266107China

The atmospheric duct is a vital radio wave *** methods of forecasting the atmospheric duct mainly include statistical analysis based on sounding observation data and mesoscale numerical model-based *** former can provide accurate duct information but is highly dependent on the acquisition of data *** latter is more practical but still lacks *** paper introduces machine learning to establish a novel meteorological parameter correction model for atmospheric duct *** detail,using the weather research and forecasting(WRF)model data and spatiotemporal characteristics as input,sounding data as label and extreme gradient boosting(XGBoost)model for training,the meteorological parameter correction effect is the best,i.e.,the accuracy of forecast meteorological parameters is improved by about 65.4%.Combining the mapping relationship between meteorological parameters and corrected atmospheric refractive index(CARI),and the transition mechanism of CARI to duct parameters,a new duct forecasting mechanism is *** to the high efficiency of numerical model and the accuracy of sounding data,the new duct forecasting mechanism has excellent *** comparing the duct forecasting results,the forecasting accuracy of the new duct forecasting model is significantly higher than that of the mesoscale model.

关键词： marine atmospheric duct neural network fitting machine learning forecasting mechanism

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Theoretical research on the transport and ionization rate coefficients in glow discharge dusty plasma

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Plasma Science and technology 2020年第3期22卷 17-23页

作者： Yonggan LIANG Jian WU Hui LI Ruihuan TIAN Chengxun YUAN Ying WANG Zhongxiang ZHOU Hao TIAN School of Physics Harbin Institute of TechnologyHarbin 150001People’s Republic of China National Key Laboratory of Electromagnetic Environment(LEME) China Research Institute of Radio Wave PropagationBeijing 102206People’s Republic of China

The electron kinetic model for investigating the transport and ionization rate coefficients of argon glow discharge dusty plasma is developed from the Boltzmann *** of the electron-neutral and electron-dust collisions are considered as collision terms in the kinetic *** kinetic equation is simplified by employing the local approximation and nonlocal approach under the same discharge conditions,and the corresponding simplified kinetic equations are known as local and nonlocal kinetic equations *** the electron energy distribution function(EEDF)is obtained by numerically solving the local and nonlocal kinetic equations and the dust charging equations *** on the obtained EEDFs,the effective electron temperature,electron mobility,electron diffusion coefficient and ionization rate coefficient are calculated for different discharge *** is shown that the EEDFs calculated from the local kinetic model clearly differ from the nonlocal EEDFs and both the local and nonlocal EEDFs are also clearly different with Maxwellian *** appearance of dust particles results in an obvious decrease of high energy electrons and increase of low energy electrons when axial electric field is *** the increase of axial electric field,the influence of dust particles on the EEDFs becomes *** electron mobility and diffusion coefficients calculated on the basis of local and nonlocal EEDFs do not differ greatly to the dust-free ***,when dust density nd=10^6 cm^?3,the electron mobility increases obviously compared with the dust-free results at low axial electric field and decreases with the increasing axial electric field until they are close to the dust-free ***,electron diffusion coefficients for dusty case become smaller and decrease with the increasing axial electric *** ionization rate coefficients decrease when dust particles are introduced and they approach the dust-free results graduall

关键词： glow discharge dusty plasma kinetic model transport coefficient ionization rate coefficient

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Simulation of DC glow discharge plasma with free-moving dust particles in the radial direction

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Plasma Science and technology 2023年第9期25卷 73-81页

作者：田瑞焕梁勇敢郝书吉冯杰江晓楠李辉袁承勋吴健 National Key Laboratory of Electromagnetic Environment(LEME) China Research Institute of Radio Wave PropagationQingdao 266170People’s Republic of China School of Physics Harbin Institute of TechnologyHarbin 150001People’s Republic of China

A self-consistent fluid model is developed to investigate the radial distributions of dusty plasma parameters in a DC glow discharge,in which the extended fluid approach of plasma particles and the transport equations of dust particles are *** electrical interaction between charged dust particles is considered in the *** time evolution of radial distributions of dust density,plasma density,the radial component of electric field and the forces acting on dust particles when dust density tends to be stable,are obtained and analyzed under different discharge currents and dust particle *** is shown that the dust density structure is determined mainly by the radial electrostatic force,thermophoretic force and ion drag force in the discharge tube,and both discharge current and dust particle radius have an obvious effect on the transport processes of dust *** dust particles gather in the central region of the discharge tube for low discharge current and small dust radius,then dust voids are formed and become wider when the discharge current and dust radius *** plasma parameters in the dust gathering region are obviously affected by the dust particles due to the charging processes of electrons and ions to the dust surface.

关键词： dusty plasma glow discharge extended fluid model dust transport processes dust-void

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Composite wave-absorbing structure combining thin plasma and metasurface

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Plasma Science and technology 2023年第4期25卷 148-155页

作者：郝志安李健飞徐彬姚静锋袁承勋王莹周忠祥王晓鸥 School of Physics Harbin Institute of TechnologyHarbin 150000People's Republic of China National Key Laboratory of Electromagnetic Environment(LEME) China Research Institute of Radio Wave PropagationQingdao 266107People's Republic of China Heilongjiang Provincial Key Laboratory of Plasma Physics and Technology Harbin 150000People's Republic of China

In order to solve the thickness dependence of plasma absorption of electromagnetic waves and further reduce the backward radar scattering cross section(RCS)of the target,we designed a novel composite structure of a metasurface and plasma.A metasurface with three absorption peaks is designed by means of an equivalent circuit based on an electromagnetic resonance type metamaterial *** reflection and absorption of the composite structure are numerically and experimentally *** finite integration method was used to simulate a composite structure of finite size to obtain the *** experimental measurements of electromagnetic wave reflection were conducted by a vector network analyzer(keysight N5234A)and horn antennas,*** research showed that the absorption capacity of this composite structure was substantially improved compared to either the plasma or the metasurface,and it is more convenient for application due to its low plasma thickness requirement and easy fabrication.

关键词： plasma metasurface composite structure radar scattering cross section

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Numerical Simulation and Analysis of Microwave Backscattering Characteristics from Sea Surface with Breaking waves and Foam

Numerical Simulation and Analysis of Microwave Backscatterin...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Du, Pengbo Wang, Yunhua Zhang, Yushi Li, Xin Zhang, Jinpeng Hou, Chunzhi Ocean University of China The Faculty of Information Science and Engineering Qingdao China China Research Institute of Radio Wave Propagation National Key Laboratory of Electromagnetic Environment Qingdao China Laoshan Laboratory The Laboratory for Regional Oceanography and Numerical Modeling Qingdao China

ISBN: (纸本)9798350375909

In the field of ocean remote sensing and detection, the normalized scattering cross-section (NRCS), an important statistical feature of sea surface, is usually employed to assess the severity of sea state. In high sea states, the sea surface wave becomes breaking and generating foam and spray which will affect the scattering characteristic of the sea surface. This study presents a modified NRCS model for sea surface, taking into account the impacts of wave breaking and foam. Firstly, the NRCS of the non-wave breaking sea surface area is calculated utilizing the two-scale method (TSM). Then, the NRCS of the sea surface encompassing the breaking wave and foam regions is determined by integrating the breaking wave NRCS semi-empirical model and vector radiative transfer (VRT) theory. Finally, the total NRCS of the sea surface containing breaking waves and foam is derived employing the white cap coverage rate. This model modifies the NRCS of a wind-driven rough sea surface composite model with breaking waves and a foam layer at a moderate incident angle. Based on the modified model, the NRCS of the sea surface for both horizontal polarization (HH-Pol) and vertical polarization (VV -Pol) are calculated at moderate incidence angles. The validity of the modified model is verified by comparing the Geophysical model function (GMF) results. The simulation results show that the effects of spray and foam on the NRCS of the sea surface cannot be ignored, especially for the results of HH-Pol. The proposed model provides a reference for the analysis of microwave backscattering characteristics of the sea surface in high sea states. © 2024 IEEE.

关键词： Ocean currents

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Study on Radar Scattering Characteristics of Breaking wave

Study on Radar Scattering Characteristics of Breaking Wave

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Du, Pengbo Wang, Yunhua Zhang, Yanmin Cui, Jianbo Zhang, Yushi Li, Xin Ocean University of China The Faculty of Information Science and Engineering Qingdao China China Research Institute of Radio Wave Propagation National Key Laboratory of Electromagnetic Environment Qingdao China Laoshan Laboratory The Laboratory for Regional Oceanography and Numerical Modeling Qingdao China

ISBN: (纸本)9798350375909

To understand the radar scattering characteristics from breaking wave based on field experiment measurement are of great benefit for ocean remote sensing and ocean target recognition. It is well known that waves originating from deep water tend to break near the shore due to the shallowness of the water. In this study, breaking waves caused by shallow water depth near shore were used to investigate the radar scattering mechanisms associated with wave breaking. An Ultra-wideband radar C-band radar backscatter measurements was conducted at incident angles ranging from 20° to 60° with both horizontal polarization (HH-Pol) and vertical polarization (VV-Pol). Our research encompassed the investigation of normalized radar cross section (NRCS), and the Doppler characteristics of breaking waves. The experimental results indicated a substantial increase in radar returns, and the HH-to-VV polarization ratio approached unity near the breaking crests. In addition, the frequency shift and the band width of the Doppler spectrum of the scattered fields from breaking waves are both increasing. And the Doppler spectrum have multiple spectral peaks due to the stronger scattering intensity and higher velocity of the breaking waves. © 2024 IEEE.

关键词： Radar cross section

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On the radar frequency dependence of polar mesosphere summer echoes

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Earth and Planetary Physics 2020年第6期4卷 571-578页

作者： ShuCan Ge HaiLong Li Lin Meng MaoYan Wang Tong Xu Safi Ullah Abdur Rauf Abdel Hannachid School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China School of Physics University of Electronic Science and Technology of ChinaChengdu 610054China National Key Laboratory of Electromagnetic Environment China Research Institute of Radio Wave PropagationQingdao 266107China Department of Meteorology Stockholm UniversitySE-106-91StockholmSweden

Polar mesosphere summer echoes(PMSEs)are very strong radar echoes in the polar mesopause in local *** we present the frequency dependence of the volume reflectivity and the effect of energetic particle precipitation on modulated PMSEs by using PMSEs observations carried out by European Incoherent SCATter(EISCAT)heating equipment simultaneously with very high frequency(VHF)radar and ultra high frequency(UHF)radar on 12 July *** to the experimental observations,the PMSEs occurrence rate at VHF was much higher than that at UHF,and the altitude of the PMSEs maximum observed at VHF was higher than that at *** regions were observed by VHF radar between high energetic particle precipitation and the *** addition,highfrequency heating had a very limited impact on PMSEs when the UHF electron density was enhanced because of energetic particle *** addition,an updated qualitative method was used to study the relationship between volume reflectivity and *** volume reflectivity was found to be inversely proportional to the fourth power of radar *** theoretical and experimental results provide a definitive data foundation for further analysis and investigation of the physical mechanism of PMSEs.

关键词： Polar mesosphere summer echoes artificial electron heating volume reflectivity energetic particle precipitation

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An unfuzzy acquisition algorithm based on matched filtering for BOC(n,n)

An unfuzzy acquisition algorithm based on matched filtering ...

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第九届中国卫星导航学术年会

作者： Xiyan SU Fang HAO Yuanfa JI Weimin ZHEN Baoguo YU Xingli GAN Guangxi Key Laboratory of Precision Navigation Technology and Application Guilin University of Electronic Technology State key laboratory of satellite navigation system and equipment technology Key Laboratory of radio wave environment and modeling technology

Due to ambiguous acquisition caused by multiple peaks of auto-correlation function(ACF) of Binary Offset Carrier(BOC) modulation technology,an Odd-even Correlation Side-peak Cancellation technology(OCSCT) is proposed in this *** side-peak elimination is obtained by multiplying and transforming the odd-even branch and received *** order to make full use of the received signals and further improve the acquisition performance,a corresponding optimization algorithm is put *** methods of BPSK-LIKE,ASPe CT and this paper are analyzed and *** results show that the proposed side-peak elimination method can effectively solve the acquisition ambiguity problem,and reduce the span of the main peak to half a chip,which further improves the acquisition *** with the ASPe CT method,the acquisition sensitivity,and the peak to average ratio is increased by 2 dB,10%,*** the calculation amount is reduced by about 50.11%.

关键词： Satellite navigation Binary Offset Carrier Unambiguous acquisition Side-peak elimination half chip

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