Modified Theory Of Physical Optics Research Articles

Çizgisel Kaynak ile Odak Dışı Beslenen Bir Parabolik Reflektörden Kırınan Alanlar

Fields of a line source diffracted by a cylindrical parabolic Perfectly Electric Conducting (PEC) reflector are investigated by employing the scattering integral of the Modified Theory of Physical Optics (MTPO). The reflector that is symmetrically located with respect to x-axis is offset-fed by a line source. The line source is lying parallel to the z-axis and off the focus of the reflector. Diffracted fields are evaluated asymptotically by means of the Edge Point Method. An approximate way of expressing uniform diffracted fields is used by utilizing the Signum and Fresnel functions together to overcome the non-uniform situations. Total scattered, diffracted, and reflected fields are plotted numerically for some parameters such as parabola width and location angle of the line source in the problem.

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Modified theory of physical optics (MTPO) solution for a soft/hard strip is analyzed. It is shown that this solution is incorrect because the MTPO Green function does not satisfy boundary conditions. Defects of MTPO in calculations of fringe waves are also noticed.

Comments on “Wave diffraction by a soft/hard strip: Modified theory of physical optics solution”

Modified theory of physical optics (MTPO) solution for a soft/hard strip is analyzed. It is shown that this solution is incorrect because the MTPO Green function does not satisfy boundary conditions. Defects of MTPO in calculations of fringe waves are also noticed.

Uniform scattered fields from a perfectly conducting parabolic reflector with modified theory of physical optics

Modified Theory of Physical Optics (MTPO) is used to solve the scattering problem from the curvilinear surfaces. The physical optics (PO) current, on the scaterers’ and aperture surfaces are the main elements of the method. These currents are the factors of the integral equation which leads to the result with the stationary phase method and edge-point technique. MTPO is a method to evaluate the edge diffraction fields scattering from different canonical shapes in addition to reflected fields. In this paper MTPO method is to be briefly explained. Then, scattering (reflection+diffraction) problem on perfectly conducting (PEC) parabolic surface will be studied by this method. Moreover, the comparison with PO method will be done to prove the validity of the MTPO solution. There exist some other problems for different geometries which can be solved by MTPO method.

Integral theory of diffraction for material junctions

A new approach to the scattering problem of waves by junctions is developed with the aid of the modified theory of physical optics (MTPO). The relation between the fundamental MTPO integral and the Fresnel function is given as a theorem with its proof. Then the integrals relation with the geometrical optics (GO) and diffracted waves is put forth with a theorem on the uniform asymptotic evaluation of scattering integrals. A new definition is introduced for the scattering process and it is shown that the solutions of some problems, related with material half-planes and junctions can be obtained easily by only evaluating the GO fields according to the new definition of the scattering phenomenon. The scattered and diffracted fields can be derived directly in terms of the MTPO integrals as a result of the relation between the GO and scattered waves. The resultant diffracted field expressions are investigated numerically.

Reply to Comments on “On the Modified Theory of Physical Optics” $ $

In our recent paper, we have discussed and shown that modified theory of physical optics (MTPO) violates the fundamental laws of GO and because of that does not satisfy the Helmholtz equation. Then, we have illustrated that MTPO fringe waves are incorrect in vicinity of the geometrical optics (GO) boundaries of incident and reflected waves.

Comments on “On the Modified Theory of Physical Optics” $ $

In our recent paper, we have discussed and shown that modified theory of physical optics (MTPO) violates the fundamental laws of GO and because of that does not satisfy the Helmholtz equation. Then, we have illustrated that MTPO fringe waves are incorrect in vicinity of the geometrical optics (GO) boundaries of incident and reflected waves.

On the Modified Theory of Physical Optics

Basic features of the modified theory of physical optics (MTPO) are discussed on the example of scattering at perfectly reflecting half-planes and wedges. It is shown that violations of the geometrical optics (GO), introduced in this technique, result in the MTPO solutions which do not satisfy the Helmholtz equation. They are incorrect at a finite distance from a scattering object; however it can be considered as sort of approximations for the field at a large distance from an edge and away from the GO boundaries.

Uniform Diffracted Fields from a Perfectly Conducting Cylindrical Reflector with Modified Theory of Physical Optics

The uniform diffracted fields are calculated on PEC cylindrical reflector by Modified Theory of Physical Optics (MTPO). It is aimed to convert the noncontinuous solution to a continuous solution by finding a uniform equation which does not contain any expression converging to 0 in the denominator part. Three axioms of MTPO theory are used to construct the integral equations for the perfectly electrically conducting surface application. The “edge-point” technique is used to find the diffracted field, and uniform solution is to be found via “detour parameter(s).” Finally, the obtained results are to be compared with the nonuniform ones, numerically.

Impedance surface diffraction analysis for a strip with the boundary diffraction wave theory

The content of the present paper is mainly about the application of the boundary diffraction wave theory to an impedance strip. This method reduces the diffraction surface integrals to line integrals. Hence, line integral directly gives the diffraction integral. Evaluation of diffraction integral gives only the diffracted fields. The vector potential which is used for the construction of the line integral is reduced to the modified theory of physical optics (MTPO) integral. With the assistance of this method diffracted fields are directly obtained and investigated numerically.

Analysis of diffracted fields with the extended theory of the boundary diffraction wave for impedance surfaces

Uniform diffracted fields from impedance surfaces are investigated by the extended theory of boundary diffraction wave (ETBDW). The new vector potential of the ETBDW is constructed by considering the pseudoimpedance boundary condition. The method is applied to the diffraction problem from an impedance half-plane. It is shown that the total fields from an impedance half-plane reduce to the case of a perfectly electric or magnetic conducting and opaque half-plane for special values of surface impedance. The total and diffracted fields are compared numerically with the exact solution for the impedance half-plane and modified theory of physical optics (MTPO) solution for an impedance wedge. The numerical results show that the field expressions are in very good agreement with the exact and MTPO solutions.

Diffraction of homogeneous and inhomogeneous plane waves by a planar junction between perfectly conducting and impedance half-planes

The problem of diffraction of homogeneous and inhomogeneous plane waves at the discontinuity formed by perfectly conducting and impedance half-planes is examined by the method of modified theory of physical optics (MTPO). The MTPO integral of the reflected scattered waves by the perfectly conducting half-plane is reconstructed in order to include the effect of the diffracted wave coming from the edge of the impedance half-plane. The integrals are evaluated by a uniform asymptotic method. The results are plotted numerically and compared with the literature.

Modified theory of physical optics solution of impedance half plane problem

The scattering of electric polarized plane waves from an impedance half plane problem is examined by the method of modified theory of physical optics (MTPO). Two integrals, consisting of incident and reflected scattered fields, are obtained. These integrals are evaluated asymptotically by the methods of stationary phase and edge point. The obtained scattered fields are compared with the exact solution numerically.

Modified theory of physical optics approach to wedge diffraction problems

The problem of diffraction from a perfectly conducting wedge is examined with the modified theory of physical optics (MTPO). The exact wedge diffraction coefficient is compared with the asymptotic edge waves of MTPO integral and related surface currents are evaluated. The scattered electric fields are expressed by using these current components. The total, incident and reflected diffracted fields are compared with the exact series solution of the wedge problem, numerically.

Modified theory of physical optics

A new procedure for calculating the scattered fields from a perfectly conducting body is introduced. The method is defined by considering three assumptions. The reflection angle is taken as a function of integral variables, a new unit vector, dividing the angle between incident and reflected rays into two equal parts is evaluated and the perfectly conducting (PEC) surface is considered with the aperture part, together. This integral is named as Modified Theory of Physical Optics (MTPO) integral. The method is applied to the reflection and edge diffraction from a perfectly conducting half plane problem. The reflected, reflected diffracted, incident and incident diffracted fields are evaluated by stationary phase method and edge point technique, asymptotically. MTPO integral is compared with the exact solution and PO integral for the problem of scattering from a perfectly conducting half plane, numerically. It is observed that MTPO integral gives the total field that agrees with the exact solution and the result is more reliable than that of classical PO integral.