We have examined the light-scattering properties of inhomogeneous biological cells through a combination of theoretical simulations and goniometric measurements. A finite-difference time-domain (FDTD) technique was used to compute intensity as a function of scattering angle for cells containing multiple organelles and spatially varying index of refraction profiles. An automated goniometer was c...

It is known that the digital waveguide (DW) method for solving the wave equation numerically on a grid can be manipulated into the form of the standard finite-difference time-domain (FDTD) method (also known as the “leapfrog” recursion). This paper derives a simple rule for going in the other direction, that is, converting the state variables of the FDTD recursion to corresponding wave variable...

This research examines the validity of utilising a 2D multiplane FDTD acoustic model to simulate low frequency sound propagation as part of a hybrid room impulse response (RIR) synthesis system. Analytic results, pertaining to the comparison of simulated low frequency multiplane RIRs with both practical RIR measurements and 3D FDTD simulated RIRs, demonstrate that a good level of accuracy is at...

The class of problems to which the Finite-Difference Time-Domain (FDTD) method can be applied is extended through the use of near and far-field projection techniques. These methods are developed by applying the equivalence principle to a surface within the FDTD problem space. Algorithms are found to project the equivalent electric and magnetic currents on this surface to any point in space eith...

This paper presents a method for implementing off-grid boundary conditions (BCs) within Yee’s Finite-Difference Time-Domain (FDTD) method, without disturbing the existing uniform mesh or changing the standard FDTD code. Both perfect electric conductor (PEC) and perfect magnetic conductor (PMC) walls are considered. The field values at off-grid virtual boundaries are obtained by extrapolation of...

Our objective is the assessment of the accuracy of a conventional finite-difference time-domain (FDTD) code in the computation of the near- and far-field scattering characteristics of a circular dielectric cylinder. We excite the cylinder with an electric or magnetic line current and demonstrate the failure of the two-dimensional FDTD algorithm to accurately characterize the emission rate and t...

The finite difference time domain (FDTD) method is commonly used as a numerically accurate way of propagating sound. However, it requires extensive computation. We present a simple method for accelerating FDTD. Specifically, we modify the FDTD update loop to prioritize computation where it is needed most in order to faithfully propagate waves through the simulated space. We estimate for each po...

A hybrid method for analysis of electromagnetic propagation in large unbounded wave structures is presented. This method is a combination of Gaussian Beam Tracing (GBT), Gabor Expansion and the Finite Difference Time Domain method (FDTD). The input field is first expanded into a sum of Gaussian Beams (GBs) using the Gabor Expansion. The resultant GBs are launched inside the system and traced us...

We analyze the performance of finite-difference timedomain (FDTD) method implementations for 2D and 3D problems. Implementations in Fortran, C and C++ (with Blitz++ library) languages and performance tests on several hardware setups (AMD, Intel i5, Intel Xeon) are considered. The performance of implementations using traditional FDTD algorithm for the largest size of test problem is limited by t...