An inverse scattering technique for electromagnetic bistatic scattering

1969 ◽  
Vol 47 (11) ◽  
pp. 1177-1184 ◽  
Author(s):  
V. H. Weston ◽  
W. M. Boerner
Keyword(s):  
Plane Wave ◽  
Scattered Field ◽  
Convex Surface ◽  
The Body ◽  
Total Field ◽  
Convex Shape ◽  
Plane Wave Incident ◽  
Smooth Body ◽  
Equivalent Sources ◽  
The Fourier Transform

It is shown that the total field produced by a plane wave incident upon a scattering body can be expressed at all points in space as the sum of the incident field and the Fourier transform of a quantity which is related to the scattering matrix. For points exterior to the minimum convex surface enclosing the body, the scattered field is reducible to a plane-wave representation which requires knowledge of the bistatic scattered field, for a fixed frequency and direction of incidence. It is shown that for certain cases, the resulting expression for the bistatic scattered field may be employed in interior portions of the minimum convex shape (including the body) in which case it represents the field arising from a set of equivalent sources. Alternative representations are also given. A technique is presented which yields the surface of a perfectly-conducting piecewise-smooth body from knowledge of the local total field. To achieve uniqueness, the technique must be applied for at least two different frequencies. Numerical results are presented which illustrate the technique.

A 3-D Total-Field/Scattered-Field Plane-Wave Source for the FDTD Analysis of Reentry Plasma Sheath

2020 ◽  
Vol 68 (8) ◽  
pp. 6214-6225 ◽  
Author(s):  
Hailiang Wei ◽  
Yanming Liu ◽  
Lei Shi ◽  
Bo Yao ◽  
Xiaoping Li
Keyword(s):  
Plane Wave ◽  
Scattered Field ◽  
Plasma Sheath ◽  
Total Field ◽  
Wave Source ◽  
Field Plane

On the Rayleigh assumption in scattering by a periodic surface

1969 ◽  
Vol 65 (3) ◽  
pp. 773-791 ◽  
Author(s):  
R. F. Millar
Keyword(s):  
Conformal Mapping ◽  
Plane Wave ◽  
Analytic Continuation ◽  
Critical Points ◽  
Scattered Field ◽  
Wave Scattering ◽  
Elliptic Partial Differential Equations ◽  
Total Field ◽  
Periodic Surface ◽  
Plane Wave Scattering

AbstractIn treating plane wave scattering by a periodic surface, Lord Rayleigh (10) assumed that the discrete, outgoing and evanescent plane wave representation for the scattered field was valid on the surface itself. Recently, this Rayleigh assumption has been questioned and criticized. For the surface y = b cos kx on which the total field vanishes, Petit and Cadilhac(8) have demonstrated its invalidity when Kb > 0·448. The present paper discusses scattering of a wave, incident from y > 0, by an analytic periodic surface y = f(x) ( – ∞ < x < ∞), and shows that the Rayleigh assumption is valid if and only if the solution can be continued analytically across the boundary at least to the line y = minf(x). Conformal mapping and results relating to the analytic continuation of solutions to elliptic partial differential equations reduce the problem to one involving the location of singularities and critical points of a potential Green's function. Provided that the perturbation of the surface from a plane is sufficiently gentle, the validity of the Rayleigh assumption is established. For the surface y = b cos kx it is shown that the assumption is valid if Kb < γ, where γ is a positive number no greater than 0·448, the precise value of which is unknown. Possible extensions of the analysis to different or more general situations are suggested.

Measurement of the scattering of an electromagnetic wave from an electron beam

1976 ◽  
Vol 54 (7) ◽  
pp. 781-784
Author(s):  
F. Hodjat ◽  
J. A. Seeger
Keyword(s):  
Electron Beam ◽  
Electromagnetic Wave ◽  
Plane Wave ◽  
Scattered Field ◽  
Peak Power ◽  
Pulse Generator ◽  
Horn Antenna ◽  
Wave Incident ◽  
Plane Wave Incident ◽  
Uniform Plane

A uniform plane wave incident on a cylindrical electron beam is simulated using a wave guiding structure consisting of parallel planar conductors. The wave guide is fed with a horn antenna using a pulse generator providing 4 kW peak power at 1.080 GHz. Scattered field from the electron beam is measured by a probe using a cancellation technique. Measurements compare favorably with theory.

scholarly journals Diffraction of a plane wave by an almost circular cylinder

1961 ◽  
Vol 264 (1317) ◽  
pp. 246-268 ◽  
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Circular Cross Section ◽  
The Body ◽  
Maximum Deviation ◽  
Dimensional Problem ◽  
Plane Wave Incident ◽  
Method Of Solution ◽  
Watson Transformation ◽  
The Mean

The two-dimensional problem of an E-polarized plane wave incident on a perfectly conducting cylinder of almost circular cross-section is treated , the maximum deviation of the perimeter of the cross-section from a strict circle being regarded mathematically as an infinitesimal quantity whose second and higher powers are neglected. In the body of the paper the method of solution uses infinite Fourier transform techniques, but an analysis involving a Watson transformation, more traditional in this type of problem , is given in appendix A. Attention is for the most part directed to the case in which the mean radius of the cylinder is large compared to the wavelength, and the form of the solution then appropriate is examined in some detail. In particular, initial terms of asymptotic expansions in inverse powers of the mean radius to wavelength ratio are obtained for the ‘specular’ and for the ‘creeping’ contributions to the far field. It is shown that the former contributionis in agreement with that derived by the Luneberg—Kline method, and the latter with the prescription proposed by Keller. Various Bessel function results are required, some of which are derived in appendices.

scholarly journals Reflection of a Wave by a Cylindrical Mirror

1956 ◽  
Vol 9 (3) ◽  
pp. 145-150 ◽  
Author(s):  
Ll. G. Chambers
Keyword(s):  
Plane Wave ◽  
Scattered Field ◽  
Incident Field ◽  
Wave Incident ◽  
Two Dimensional ◽  
Cylindrical Mirror ◽  
Plane Wave Incident

The question of the reflection of a wave by a cylindrical mirror is of interest in a number of fields. It is a problem in which it is difficult to obtain an expression for the reflected or scattered field without recourse to physical assumptions which are sometimes somewhat dubious. An attempt was made by Sommerfeld to solve the problem of a plane wave incident upon such a perfectly conducting mirror by means of what he termed the “Non-Final Determination of Coefficients”. Unfortunately, a close examination of the problem renders it doubtful whether the method can be legitimately employed. It is possible, however, to solve the problem by expressing the scattered field in terms of the currents produced in the mirror, and finding the current generated in the mirror by an arbitrary incident field. The problem which we shall consider is the following two- dimensional one.

scholarly journals Ultrasonic Scattered Field Distribution of One and Two Cylindrical Solids with Phased Array Technique

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Xiaozhou Liu ◽  
Jian Ma ◽  
Haibin Wang ◽  
Sha Gao ◽  
Yifeng Li ◽  
...  
Keyword(s):  
Plane Wave ◽  
Field Distribution ◽  
Scattered Field ◽  
Phased Array ◽  
Simulation Analysis ◽  
Plane Waves ◽  
Theoretical Solution ◽  
Steel Matrix ◽  
Field Distributions ◽  
Scattered Fields

AbstractThe scattered fields of plane waves in a solid from a cylinder or sphere are critical in determining its acoustic characteristics as well as in engineering applications. This paper investigates the scattered field distributions of different incident waves created by elastic cylinders embedded in an elastic isotropic medium. Scattered waves, including longitudinal and transverse waves both inside and outside the cylinder, are described with specific modalities under an incident plane wave. A model with a scatterer embedded in a structural steel matrix and filled with aluminum is developed for comparison with the theoretical solution. The frequency of the plane wave ranged from 235 kHz to 2348 kHz, which corresponds to scaling factors from 0.5 to 5. Scattered field distributions in matrix materials blocked by an elastic cylindrical solid have been obtained by simulation or calculated using existing parameters. The simulation results are in good agreement with the theoretical solution, which supports the correctness of the simulation analysis. Furthermore, ultrasonic phased arrays are used to study scattered fields by changing the characteristics of the incident wave. On this foundation, a partial preliminary study of the scattered field distribution of double cylinders in a solid has been carried out, and the scattered field distribution at a given distance has been found to exhibit particular behaviors at different moments. Further studies on directivities and scattered fields are expected to improve the quantification of scattered images in isotropic solid materials by the phased array technique.

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