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We demonstrate how a tightly-focused coherent TEMmn laser beam can be computed in the finite-difference time-domain (FDTD) method. The electromagnetic field around the focus is decomposed into a plane-wave spectrum, and approximated by a finite number of plane waves injected into the FDTD grid using the total-field/scattered-field (TF/SF) method. We provide an error analysis, and guidelines for...

We present waveguide Bragg gratings with misaligned sidewall corrugations on a silicon-on-insulator platform. The grating strength can be tuned by varying the misalignment between the corrugations on the two sidewalls. This approach allows for a wide range of grating coupling coefficients to be achieved with precise control, and substantially reduces the effects of quantization error due to the...

To characterise the reflection properties of printed surfaces like FSS (Frequency Selective Surfaces) and EBG (Electromagnetic Band-Gap), it is standard to use a plane wave excitation, and then compare the phase of the incident and the reflected waves. Thus, the phase difference over the frequency can be obtained. Nevertheless, in most cases, only infinite size structures are considered. In thi...

This paper studies the enhanced efficiency of the field strength coupled into slots by using the finite difference time domain method. The coupled field strength with the different slots shape, size, and polarization direction is assisted, some useful rules are concluded. The easiest to form enhanced efficiency of field strength is rectangular slots, square slots are the second, and the most di...

Discontinuous Galerkin Time Domain Methods for Acoustics and Comparison with Finite Difference Time Domain Methods

The finite-difference time-domain (FDTD) technique has been used to model the one-dimensional (1-D) surface impedance of a lossy earth plane having discontinuities in two and three dimensions. Using a horizontal magnetic field aperture source located five cells from an absorbing boundary and 35 cells above the lossy earth plane, the surface impedance was accurately modeled at a distance of 0=50...

This paper presents a method which combines electromagnetic simulation and ultrasonic simulation to build EMAT array models. For a specific sensor configuration, Lorentz forces are calculated using the finite element method (FEM), which then can feed through to ultrasonic simulations. The propagation of ultrasound waves is numerically simulated using finite-difference time-domain (FDTD) method ...

There has been a continuous interest in the analysis of ground-penetrating radar systems and related applications in civil engineering [1]. Consequently, a deeper insight of scattering phenomena occurring in a lossy half-space, as well as the development of sophisticated numerical methods based on Finite Difference Time Domain (FDTD) method, Finite Element Method (FEM), Boundary Element Method ...

An optimal design of two dimensional (2D) hexagonal photonic bandgap (PBG) resonating micro-optical defect cavity on IV-VI lead salt material has been carried out. The nature of both the transverse electric (TE) and transverse magnetic (TM) band structure for the electromagnetic waves in the periodic triangular lattice pattern is formulated by the well-established plane wave expansion (PWE) met...