Subsurface sensing modalities such as Ground Penetrating Radar (GPR) are increasingly being used to assess the condition of aging civil infrastructure by evaluating deterioration within roadways and bridges, and to monitor the security of national borders by the detection of underground tunnels. The need to address these issues is intensifying and, while valuable data are collected using nondes...

We present two novel, fully three-dimensional (3-D) finite-difference time-domain (FDTD) schemes in cylindrical coordinates for transient simulation of electromagnetic wave propagation in complex (inhomogeneous, dispersive, and conductive) and unbounded media. The proposed FDTD schemes incorporate an extension of the perfectly matched layer (PML) absorbing boundary condition (ABC) to three-dime...

The numerical simulation of electromagnetic fields and particle interactions in accelerator components can consume considerable computational resources. By performing the same computation on fast, highly parallel GPU hardware instead of conventional CPUs it is possible to achieve a 20x reduction in simulation time for the traditional 3D FDTD algorithm. For structures that are small compared to ...

Growing interest in providing and improving radio coverage for mobile phones and wireless LANs inside buildings has recently emerged. The need of such coverage appears mainly in office buildings, shopping malls in very complex environment. Although the three dimensional FDTD method has shown great promise, the calculation time is very environment dependent and exceeds the calculation time of ra...

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...