检索结果-南通市图书馆

scattering and absorption characteristics of non-spherical cirrus cloud ice crystal particles in terahertz frequency band

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第7期29卷 120-127页

作者： Tao Xie Meng-Ting Chen Jian Chen Feng Lu Da-Wei An School of Remote Sensing and Geomatics Engineering Nanjing University of Information Science and TechnologyNanjing 210044China School of Electronic and Information Engineering Nanjing University of Information Science and TechnologyNanjing 210044China National Satellite Meteorological Centre China Meteorological AdministrationBeijing 100081China

We used discrete dipole approximation(DDA)to examine the scattering and absorption characteristics of spherical ice crystal *** this basis,we studied the scattering characteristics of spherical ice crystal particles at different frequencies and non-spherical ice crystal particles with different shapes,aspect ratios,and spatial *** results indicate that the DDA and Mie methods yield almost the same results for spherical ice crystal particles,illustrating the superior calculation accuracy of the DDA *** with the millimeter wave band,the terahertz band particles have richer scattering characteristics and can detect ice crystal particles more *** frequencies,shapes,aspect ratios,and spatial orientations have specific effects on the scattering and absorption characteristics o f ice crystal *** results provide an important theoretical basis for the design of terahertz cloud radars and related cirrus detection methods.

关键词： scattering characteristics discrete dipole approximation terahertz non-sphericalice crystal particles

Distribution characteristic of scattering field for an ellipsoidal target irradiated by an electromagnetic wave from an arbitrary direction

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2008年第9期17卷 3394-3401页

作者：李应乐黄际英王明军张家田 Institute of Electromagnetic Wave Propagation & scattering Xianyang Normal University School of Science Xidian University School of Electric Engineering Xian Shiyou University

It is of great importance for engineering applications to obtain the expression of scattering field for an ellipsoidal target irradiated by an electromagnetic wave from an arbitrary direction. Literature relevant to this problem is seldom found. In this paper, the scattering field for an ellipsoidal target is presented by utilizing the scale transformation of electromagnetic field and the rotation of coordinate system, with an electromagnetic wave projecting on the target from an arbitrary direction. The obtained result is in good agreement with the solution available from the literature if we consider the scale factors to be unity. Taking a conducting ellipsoidal target for sample, we perform the partial simulations of the ellipsoidal model and a plant leaf model by choosing different scale factors. The obtained results show that the distribution characteristic of scattering field is sensitively affected by the polarization of the incident wave and varies not much with the incident wave angle but changes with the observation point. At some points the scattering energy arrives at its maximum.

关键词： ellipsoidal target scale analysis arbitrary incidence and polarization scattering characteristics

Analysis of echo signal modulation characteristic parameters on aerial and space targets

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2023年第10期28卷 146-154页

作者： Si Chen Hai-yang Zhang Chang-ming Zhao Yu Fan Hong Chen Lin Wang School of Optics and Photonics Beijing Institute of TechnologyBeijing100081China Key Laboratory of Electro-Optical Countermeasures Test&Evaluation Technology Unit 63891 of the Chinese People's Liberation ArmyHenan461002China Key Laboratory of Optical Radiation Beijing Institute of Environmental CharacteristicsBeijing100854China

Based on the scattering characteristic,the comparison of RCS(radar cross-section)at different positions of a target in the same direction of incidence can be obtained first by extruding or deleting part of the entity.A simulation method of aerial&space targets echo characteristics(A&STEC)is proposed that is universal to aerial and space *** utilize a fixed-wing UAV(unmanned aerial vehicle)and typical missiles in *** echo signal modulation characteristic parameters are calculated theoretically by the atmospheric attenuation model,the finite element method and a MUMPS *** verification simulations show that this method can analyze the influence of the target shape,incident direction,detection position and detection frequency on echo waveform,intensity and energy *** results show that the profile of echo waveform can invert the general shape of the *** relationship between time and intensity can determine whether the target is moving towards or away from the detector in *** conclusions can provide a reference for the ballistic missile target tracking and the defense against UVA intrusion in theory.

关键词： Echo signal modulation characteristic parameters Simple targets The fixed-wing UVA Missiles scattering characteristics

LOW RCS MODIFIED DESIGN OF EXTERNAL CARRIAGE AND ANALYSIS OF ITS scattering CHARACTERISTIC

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2000年第3期13卷 152-156页

作者：马东立黄沛霖北京航空航天大学北京 1 0 0 0 83

An external carriage and a wing have a high radar cross section (RCS) level in a wide range of angles of pitch because they form an efficient corner reflector. Coupling scattering between the external carriage and the wing is controlled by designing a saw tooth structure of the external carriage on condition that the wing structure is not changed. A low RCS saw tooth scheme of the external carriage is given in the paper. The ray tracing method and the physical theory of diffraction are used to calculate the radar scattering characteristics of low RCS structures of the external carriage and wing. The results show that the saw tooth scheme of the external carriage is feasible and effective for low RCS design.

关键词： external carriage radar cross section design scattering characteristics