This paper reports the simulation of phased array ultrasonic wave propagation using Finite Difference Time Domain (FDTD) method to image crack like defects in Aluminum Blocks and Stainless Steel elbow sections. Inclined crack like defects have been considered for the simulation. Experiments were also performed on an Aluminum block with inclined embedded cracks various sizes in order to validate...

This paper describes a new functional electromagnetic cell material (EMCM) for EMC use. This novel material is composed of passive or active micro-electronic circuit elements and they are connected with loss or conductive wirings. If it is composed of active circuit elements, this material is able to exhibit a special feature of changeable characteristics of EM-wave absorber. As an example of E...

This paper presents two-dimensional (2-D) finite difference time domain (FDTD) simulations of low-loss rightangle waveguide bends, T-junctions and crossings, based on high index-contrast waveguides. Such structures are essential for the dense integration of optical components. Excellent performance characteristics are obtained by designing the waveguide intersection regions as low-Q resonant ca...

A numerical model for scattering from sea ice based on the finite difference time domain (FDTD) technique is presented. The sea ice medium is modeled as consisting of randomly located spherical brine scatterers with a specified fractional volume, and the medium is modeled both with and without a randomly rough boundary to study the relative effects of volume and surface scattering. A Monte Carl...

We theoretically study channel plasmon-polaritons (CPPs) with a geometry similar to that in recent experiments at telecom wavelengths (Bozhevolnyi et al., Nature 440, 508 (2006)). The CPP modal shape, dispersion relation, and losses are simulated using the multiple multipole method and the finite difference time domain technique. It is shown that, with the increase of the wavelength, the fundam...

This paper presents numeric simulations related to sensing through the wall radar technologies. Our computational approaches include the Finite Difference Time Domain (FDTD) algorithm and the shooting and bouncing ray technique (Xpatch). We analyze the radar signatures of the human body and other objects, in free-space and inside a room. The emphasis is on radar scattering phenomenology, with r...

The Kelly-Lochbaum transmission-line model of the vocal tract started the discrete-time modeling of speech production. More recently similar techniques have been developed in computer music towards a more generalized methodology. In this paper we will study the application of mixed physical modeling to speech production and speech synthesis. These approaches are Digital Waveguides (DWG), Finite...

In this paper it is shown that the inaccuracy in the beam propagation method based on the finite difference scheme, introduced by the use of the slowly varying envelope approximation, can be overcome in an effective way. By the introduction of a perturbation expansion the accuracy can be improved as much as wanted, often nearly without any increase of the computation time. An error analysis is ...

Different electromagnetic theories have been applied in order to understand the interaction of the electromagnetic radiation with diffraction gratings. Kogelnik’s Coupled Wave Theory, for instance, has been applied with success to describe the diffraction properties of sinusoidal volume gratings. Nonetheless the predictions of Kogelnik’s theory deviate from the actual behaviour whenever the hol...