Comparison of time-domain uniform asymptotic solution with experimental-numerical results for transient scattered fields by a cylindrically curved open surface

2007 ◽  
Author(s):  
Keiji Goto ◽  
Toshihide Ajiki ◽  
Hideaki Yamada ◽  
Toru Kawano ◽  
Toyohiko Ishihara
Keyword(s):  
Asymptotic Solution ◽  
Time Domain ◽  
Numerical Results ◽  
Open Surface ◽  
Scattered Fields

Analysis for Scattering of Non-homogeneous Medium by Time Domain Volume Shooting and Bouncing Rays

2021 ◽  
Vol 36 (3) ◽  
pp. 245-251
Author(s):  
Jun Li ◽  
Huaguang Bao ◽  
Dazhi Ding
Keyword(s):  
Time Domain ◽  
Electromagnetic Scattering ◽  
Electromagnetic Waves ◽  
High Efficiency ◽  
Homogeneous Medium ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Transient Electromagnetic ◽  
Frequency Domain Methods ◽  
Scattered Fields

In order to evaluate scattering from hypersonic vehicles covered with the plasma efficiently, time domain volume shooting and bouncing rays (TDVSBR) is first introduced in this paper. The new method is applied to solve the transient electromagnetic scattering from complex targets, which combines with non-homogeneous dielectric and perfect electric conducting (PEC) bodies. To simplify the problem, objects are discretized into tetrahedrons with different electromagnetic parameters. Then the reflection and transmission coefficients can be obtained by using theory of electromagnetic waves propagation in lossy medium. After that, we simulate the reflection and transmission of rays in different media. At last, the scattered fields or radiation are solved by the last exiting ray from the target. Compared with frequency-domain methods, time-domain methods can obtain the wideband RCS efficiently. Several numerical results are given to demonstrate the high efficiency and accuracy of this proposed scheme.

Modeling near‐field GPR in three dimensions using the FDTD method

Geophysics ◽  
1997 ◽  
Vol 62 (4) ◽  
pp. 1114-1126 ◽  
Author(s):  
Roger L. Roberts ◽  
Jeffrey J. Daniels
Keyword(s):  
Electrical Properties ◽  
Finite Difference ◽  
Time Domain ◽  
Near Field ◽  
Characteristic Impedance ◽  
Fdtd Method ◽  
Three Dimensions ◽  
Field Pattern ◽  
Scattered Fields ◽  
Transmitting Antenna

Complexities associated with the theoretical solution of the near‐field interaction between the fields radiated from dipole antennas placed near a dielectric half‐space and electrical inhomogeneities within the dielectric can be overcome by using numerical techniques. The finite‐difference time‐domain (FDTD) technique implements finite‐difference approximations of Maxwell's equations in a discretized volume that permit accurate computation of the radiated field from a transmitting antenna, propagation through the air‐earth interface, scattering by subsurface targets and reception of the scattered fields by a receiving antenna. In this paper, we demonstrate the implementation of the FDTD technique for accurately modeling near‐field time‐domain ground‐penetrating radar (GPR). This is accomplished by incorporating many of the important GPR parameters directly into the FDTD model. These variables include: the shape of the GPR antenna, feed cables with a fixed characteristic impedance attached to the terminals of the antenna, the height of the antenna above the ground, the electrical properties of the ground, and the electrical properties and geometry of targets buried in the subsurface. FDTD data generated from a 3-D model are compared to experimental antenna impedance data, field pattern data, and measurements of scattering from buried pipes to verify the accuracy of the method.

Time-Domain Line-Integral Representations of Physical-Optics Scattered Fields

2017 ◽  
Vol 65 (1) ◽  
pp. 309-318 ◽  
Author(s):  
Tian Tian Fan ◽  
Xiao Zhou ◽  
Wen Ming Yu ◽  
Xiao Yang Zhou ◽  
Tie Jun Cui
Keyword(s):  
Time Domain ◽  
Integral Representations ◽  
Physical Optics ◽  
Line Integral ◽  
Scattered Fields

Anisotropic, Multiply Scattered Radiation From an Arbitrary, Cylindrical Source in an Infinite Slab

1965 ◽  
Vol 87 (2) ◽  
pp. 167-172 ◽  
Author(s):  
J. H. Chin ◽  
S. W. Churchill
Keyword(s):  
Approximate Analytical Solution ◽  
Numerical Results ◽  
Source Strength ◽  
Open Surface ◽  
Scattered Energy ◽  
Infinite Slab ◽  
Cylindrical Source ◽  
Scattering Material ◽  
Reflecting Surface ◽  
Oil Particles

An approximate, analytical solution is developed for the intensity of electromagnetic radiation resulting from a line or cylindrical source located within and normal to the boundaries of an infinite slab of purely scattering material. The source strength is allowed to vary arbitrarily along the line or cylinder, and the slab is considered to have one absorbing (or open) surface and one partially reflecting surface. The problem represents an idealization of the attenuation of thermal radiation from a nuclear fireball within a layer of fog or a dispersion of oil particles. The six-flux resolution of scattered energy proposed by Chu and Churchill is utilized. In general, machine computations are needed to obtain numerical results. Approximations are suggested for use in the indicated computations. Illustrative numerical results are presented.

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