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- Yusuf Umul
- Optics express
- 2004

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… (More)

- Yusuf Z Umul
- Journal of the Optical Society of America. A…
- 2007

Diffraction of evanescent plane waves by a resistive half-plane is examined. The scattering integrals are constructed with the modified theory of physical optics. These integrals are evaluated uniformly by using an unusual method. The scattered fields of evanescent waves are obtained by giving the angle of incidence a complex value. The diffracted waves are… (More)

- Weng Cho Chew, Y. Z. Umul
- 2010

Diffraction of scalar plane waves by resistive surfaces are investigated by defining a new boundary condition in terms of the Dirichlet and Neumann conditions. The scattering problems of waves by a resistive half-plane and the interface between resistive and perfectly magnetic conducting half-planes are examined with the developed method. The resulting… (More)

- Yusuf Z Umul
- Optics letters
- 2005

Simple exponential functions that approach zero for reflection and shadow boundaries are considered to cancel the infinite values of diffraction coefficients at these regions. This method is applied to a wedge diffraction coefficient, and the resultant uniform coefficient is compared with the exact diffracted fields numerically.

- Yusuf Umul
- Optics express
- 2005

The scattered fields from a black half plane which absorbs all the incoming electromagnetic energy are evaluated by defining a new modified theory of physical optics surface current. This current eliminates the reflected fields, coming from the first stationary point of the reflection integral and only creates a reflected diffracted field. The incident… (More)

- Yusuf Umul
- Optics express
- 2005

Fresnel integral is modeled with three equivalent functions. The first function is derived by considering the sum of the first term of the Fresnel integral's asymptotic expansion {F(x)} and an exponential function which approaches to infinity at the zero of the Fresnel function's argument and has the properties of a unit step function. The second one is the… (More)

- Yusuf Z Umul
- Journal of the Optical Society of America. A…
- 2008

Kirchhoff's theory of diffraction is derived by transforming the exact solution of Sommerfeld into surface integrals for the half-plane problem. It is shown that the exact solution directly yields the integral theorem of Kirchhoff in the context of the modified diffraction theory of Kirchhoff. The line integrals of Young-Rubinowicz are also derived by… (More)

- Yusuf Ziya Umul
- Journal of the Optical Society of America. A…
- 2011

The solution of the scattering problem of waves by a half-screen with equal face impedances, which was introduced by Malyughinetz, is transformed into a physical optics integral by using the inverse edge point method. The obtained integral is applied to the diffraction problem of plane waves by an impedance truncated circular cylinder and the scattered… (More)

- Yusuf Z Umul
- Journal of the Optical Society of America. A…
- 2008

The scattering of the radiated fields of a line source by a cylindrical parabolic reflector, which has impedance boundary conditions on its surface, is obtained by using the surface integrals of the modified theory of physical optics. The reflected geometrical optics and edge diffracted fields are evaluated by using the asymptotic methods. The scattered… (More)

- Yusuf Z Umul
- Journal of the Optical Society of America. A…
- 2007

A uniform diffracted field is obtained in terms of Fresnel functions with complex argument by subtracting the unit step function from the Fresnel integral. The method is applied to the problem of diffraction of inhomogeneous plane waves by a perfectly conducting half-plane and wedge. The results are plotted numerically and compared with results reported in… (More)