Gaussian beam scattering from a conducting cylinder partially buried in a ground plane

The problem of scattering from an infinitely long conducting cylinder that is partially buried in a perfectly conducting ground plane due to an obliquely incident gaussian beam is solved by an exact procedure based on the method of images by first adopting a simplification originally proposed by Kozaki. The incident and the specularly reflected fields are expressed in terms of cylindrical vector wave functions multiplied by a weighting function which involves the beam parameters like the radial distance of the source and beam width. The scattered fields originating from the cylinder and its image in the ground plane are expressed in terms of cylindrical vector wave functions. The boundary conditions on the surface of the cylinder are then imposed and this procedure leads to a coupled infinite system of equations for the even and odd mode expansion coefficients of the scattered field. These equations are solved numerically for the case of cylinders having electrical radius in the Rayleigh and resonance regions. Both the transverse magnetic and transverse electric polarizations of the incident beam wave are considered and some representative numerical results for the scattered far-field are presented in graphical form. The magnitude of the induced current for the TM polarization is calculated and compared with the corresponding case of plane wave incidence.     

Research into Influence of Gaussian Beam on Terahertz Radar Cross Section of a Conducting Cylinder

In RCS measurement, usually the incident beam is a Gaussian beam or a similar beam source; however, in the theoretical RCS estimation, usually a plane wave is assumed as the incident beam for sake of simplicity. In this paper, the RCS of an infinite perfect conducting cylinder is estimated. In the estimation, the influence of a 2.52 THz laser beam on RCS is studied and the RCS in dependence with scattering angle and some other factors is obtained after the change of RCS equation; meanwhile, comparisons of RCS when the incident beam is a plane wave and a Gaussian beam respectively, are also given. The estimation results show, when the cylinder radius is 10 mm, choosing a beam width of 40 mm can keep the relative error less than 0.48 dB.     

Scattering of gaussian beam by a ferrite cylinder

The scattering of a Gaussian beam by a ferrite cylinder is analyzed using two methods. The spatial pictures in the amplitude of the total Gaussian beam near the cylinder resulting from the two methods are both clarified and compared. The scattering by a ferrite cylinder coating a dielectric sleeve is also presented.     

High frequency scattering of a Gaussian beam by a conducting cylinder

When the radius of the cylinder is much larger than the wavelength, an approximate expression for the scattering of a Gaussian beam by a conducting cylinder is obtained by using Watson transformation. The beam fields in shadow region and illuminated region are, respectively, derived from residue theorem and stationary phase method. In order to check the theory, comparisons for scattering pattern and field variation in space were made. Numerical examples of the scattering patterns forw/lambda geqleq a_{0}/lambda gg 1 (w, a_{0} lambdabeing the beamwidth, the radius of cylinder, and the wavelength) are also illustrated.     

Depolarization of a circularly polarized wave by an infinite cylinder

Depolarization of a circularly polarized radar signal, scattered by an infinite cylinder, is examined over a large range of values for the electrical circumferenceka. Experimental data were obtained to verify the prediction that the circular depolarization ratio exceeds unity at normal incidence for a sizeable range ofkaless than unity. Backscattering widths and field phases are analyzed for linear and circular polarizations as they relate to scattering from the infinite cylinder.     

高斯光圆柱太赫兹雷达散射截面的影响

通过对缩比模型的太赫兹波段雷达散射截面(RCS)测量,可以获得微波波段全尺寸目标的RCS值,因此,RCS估算和测量是当前太赫兹重要的应用技术之一。RCS估算中,通常假定入射光为均匀平面波,但在实际测量应用中,常常采用发射类似高斯光束的太赫兹源。进行了横电波情况高斯光束入射时,无限长理想导体圆柱的太赫兹雷达散射截面估算。仿真研究了2.52 THz激光准直入射和相位变化对后向雷达散射截面的影响,给出了RCS与散射角的变化曲线;同时与均匀平面波入射结果进行了比较分析。仿真结果表明,在测量圆柱半径10 mm且入射光距圆柱轴心距离1 m处的后向RCS时,用光斑半径30 mm的高斯光束较好。     

粗糙地面上相邻两树干的电磁散射模型

用有限长多层介质圆柱模拟实际的树干,建立了基于粗糙地面上相邻两树干电磁散射模型。用迭代方法和等效原理,求解了多层介质圆柱的散射矩阵。用互易原理求解了相邻有限长多层介质圆柱包括其二次散射场在内的解析表达式。     

Scattering by a nihility cylinder

The total scattering and the extinction efficiencies of a nihility cylinder of infinite length and circular cross-section are identical and independent of the polarization state of a normally incident plane wave.     

THE ELECTROMAGNETIC SCATTERING OF A RADIALLY INHOMOGENEOUS DIELECTRIC CYLINDER

A new method is demonstrated for solving the electromagnetic scattering problemof a radially inhomogeneous lossless or lossy dielectric cylinder by Fourier series expansion.Com-pared with other methods,the method is simpler in numerical calculation and can be used forsolving scattering problems of a cylinder due to an arbitrary incident electromagnetic beam.     

Backscatter RCS for TE and TM excitations of dielectric-filledcavity-backed apertures in two-dimensional bodies

Transverse electric (TE) and transverse magnetic (TM) scattering from dielectric-filled, cavity-backed apertures in two-dimensional bodies are treated using the method of moments technique to solve a set of combined-field integral equations for the equivalent induced electric and magnetic currents on the exterior of the scattering body and on the associated aperture. Results are presented for the backscatter radar cross section (RCS) versus the electrical size of the scatterer for two different dielectric-filled cavity-backed geometries. The first geometry is a circular cylinder of infinite length which has an infinite length slot aperture along one side. The cavity inside the cylinder is dielectric filled and is also of circular cross section. The two cylinders (external and internal) are of different radii and their respective longitudinal axes are parallel but not collocated. The second is a square cylinder of infinite length which has an infinite length slot aperture along one side. The cavity inside the square cylinder is dielectric-filled and is also of square cross section     

Scattering by a lossy dielectric circular cylindrical multilayer numerical values

The theoretical scattering solution for a plane wave incident normally on a lossy dielectric multilayer circular cylinder of infinite length is outlined. Numerical values of the modal scattering coefficient for TE and TM modes are given for several single and multilayer cylinders. Verifications of the results are described. The values may serve as reference data.     

The Electromagnetic Problems of a Cylinder or Elliptic Cylinder with Infinite Axial Slits and Others

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Diffraction of an H-polarized electromagnetic wave by a circular cylinder with an infinite axial slot

A comparison of three methods of solution for the problem of scattering and diffraction of a transverse electric (TE) polarized plane wave by an infinite circular cylinder having an infinite axial slot is presented. In one method of solution, the aperture field integral equation (AFIE) method, the fields in and around the cylinder are found from the apertureE-field and the Green's functions for the interior and exterior of a cylinder. In the other two methods, the fields are determined from the surface current, which is obtained by solution of theH-field integral equation (HFIE) or theE-field integral equation (EFIE). The field in the aperture of the cylinder is found from the three methods, and the advantages and disadvantages of each method of solution are discussed. In addition, it is also shown that for shell thickness less than 1/20 of a wavelength, the aperture fields do not differ signifcantly from those of an infinitely thin shell cylinder.     

Scattering from an infinite cylinder of small radius embedded intoa dielectric one

In this paper the scattering from an infinite metallic or dielectric cylinder of electrically small radius, embedded into a dielectric cylinder, is considered. The problem is solved by the method of separation of variables, in conjunction with translational addition theorems. Analytical expressions are obtained for the scattered field and the various scattering cross-sections, when the radius of the inner cylinder is electrically small. Both polarizations are considered for normal incidence. Numerical results are given for various values of the parameters and for metallic or dielectric inner cylinder     

Scattering of a Monopolar TE-Polarized Electromagnetic Pulse on an Ideally Conducting Cylinder

Journal of Communications Technology and Electronics - Abstract—The problem of scattering on an ideally conducting infinite cylinder of a monopolar electromagnetic pulse, the electric field...     

Electromagnetic scattering from an eccentric multilayered circularcylinder

Electromagnetic scattering from an eccentric multilayered, homogeneous, circular cylinder is derived rigorously by using a boundary value mode-matching approach. The layers are assumed to be infinite in length and their axes are parallel to each other but their centers may have arbitrary coordinates. The composite arrangement is illuminated by a cylindrical wave from a line source of infinite extent in a direction parallel to the cylinder axis. The problem is two-dimensional and the solution to both types of polarization is presented. The effects of various geometrical and electrical parameters on the near- and far-field patterns are examined     

Electromagnetic scattering from a coaxial dielectric circularcylinder loading a semicircular gap in a ground plane

An exact dual series solution of a plane wave incident on a coaxial dielectric circular cylinder imbedded in a semicircular gap of a ground plane is presented. Both TM and TE cases are considered here. The scattered field is represented in terms of an infinite series of cylindrical waves with unknown coefficients. By applying the boundary conditions and employing the partial orthogonality of the trigonometric functions the scattering coefficients are obtained. The resulting infinite series is then truncated to a finite number of terms to produce numerical results. For the sake of comparison with the published data some special cases are introduced first. The comparisons showed excellent agreement in all cases     

On Multiple Scattering of Radiation by an Infinite Grating of Dielectric Circular Cylinders at Oblique Incidence

A rigorous analytical representation for the multiple scattering coefficients of the fields radiated by an infinite grating of dielectric circular cylinders excited by an obliquely incident plane electromagnetic wave is derived in terms of the “well-known scattering coefficients of an isolated dielectric cylinder at oblique incidence” and “Schlömilch series”. In addition, a generalized sum-integral grating equation is acquired for the multiple scattered amplitude of a cylinder at oblique incidence in the grating in terms of the scattering coefficients of the insulating dielectric circular cylinder at oblique incidence.     

Whispering-gallery and Luneburg-lens effects in a beam-fed circularly layered dielectric cylinder

The whispering-gallery (WG) mode excitation and Luneburg (1941) lens (LL) effects are studied for a lossy circularly layered dielectric cylinder illuminated by a beam field. The latter is simulated by the complex source-point (CSP) beam. Exact series solution to the wave scattering problem is used to obtain the far-field patterns and directivity. The WG mode effect is shown to undermine the LL performance.     

Two approaches to solving the problem of diffraction by a cylindrical body with a coordinate-dependent refractive index

An algorithm based on solving a two-dimensional integral equation for the problem of diffraction by an infinite cylindrical body with a coordinate-dependent refractive index is proposed. For the diffraction by a circular cylinder, rigorous approach reduced to solving the Helmholtz equation by expanding the field in a combined basis of splines and trigonometric functions is used. The comparison of two methods for the case when the squared wavenumber depends parabolically on the x-coordinate is performed. The method on the basis of the integral equation was tested on a problem of plane-wave scattering by a cylinder with an elliptic or a rectangular cross section under the assumption that the wavenumber of the medium inside the cylinder may be constant. A special case of the diffraction by an inhomogeneous circular cylinder from a metamaterial is also considered.