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Reflections from boundaries of the FDTD computational domain lead to inaccurate, even unstable codes when dealing with problems involving double negative (DNG) materials. Here, an efficient and simple algorithm is presented for terminating FDTD in DNG medium which is based on first and second order Mur's absorbing boundary conditions (ABC). FDTD update equations for Mur's ABC formulations are obtained from frequency domain one-way wave equations using piecewise linear recursive convolution (PLRC) method. Numerical examples are given both for 1D and 2D scenarios to demonstrate the validity and stability of the proposed Mur formulations, and its advantages over uniaxial perfectly matched layer (UPML) in reducing computational time and memory requirements. [ABSTRACT FROM AUTHOR]

The paper examines diffraction at rounded wedges with perfectly conducting faces. This topic was a subject of many publications which investigated mainly the total diffracted waves. In the present paper, we calculate specifically their fringe components to illustrate their sensitivity to the edge curvature. Such fringe waves provide substantial contributions to the scattered field in certain directions and represent a key element in extension of the physical theory of diffraction (PTD) for objects with rounded edges. [ABSTRACT FROM AUTHOR]

Electromagnetic diffraction modelling and recent numerical simulation approaches, on the canonical 2D non-penetrable wedge scattering problem, are reviewed in this introduction paper. [ABSTRACT FROM AUTHOR]

A novel method is introduced for calculating fringe currents and fringe waves around the tip of a perfectly reflecting wedge under line source illumination. The time-domain fringe (non-uniform) currents are extracted with the finite-difference time-domain (FDTD) method. These currents are then fed into a free-space FDTD and fringe waves are excited. Alternatively, fringe waves are also obtained using the Green's function approach. The validation of the proposed method and the verification of the results are done against the physical theory of diffraction (PTD) as well as the method of moments (MoM). The factors affecting the accuracy are also discussed. [ABSTRACT FROM AUTHOR]

Scattering from edges and/or tips (i.e., diffraction) has long been modeled using different approaches. Initially, it was handled analytically using high frequency asymptotics (HFA). Parallel to the development in computer technology diffraction has begun to be modeled using numerical approaches also. Here, method of moments (MoM) is used to model the canonical wedge scattering problem and a novel, generally applicable procedure is introduced to extract diffracted fields and diffraction coefficients. [ABSTRACT FROM AUTHOR]

A novel Matlab-based diffraction tool for the investigation of scattered fields around a two-dimensional Perfectly Electric Conductor (PEC) wedge is introduced. Analytical (Exact by Integral, as well as some High Frequency Asymptotic (HFA) techniques) and numerical (Finite-Difference Time-Domain (FDTD)) models are included. The FDTD staircase modeling problems are removed by the application of Dey-Mittra Conformai approach. [ABSTRACT FROM AUTHOR]

This paper presents a comparative study of some analytical and numerical techniques in the solution of a classical problem of electromagnetic scattering from single and double knife edge above ground. The results of the analytical exact and asymptotic techniques (such as uniform theory of diffraction, parabolic equation diffraction method) are compared with the two-way split-step parabolic equation method (SSPE), through several numerical simulations. Salutary discussions on their capabilities and limitations are presented. Codes used in the simulations are provided in the end. [ABSTRACT FROM AUTHOR]