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 have developed a systematic design process for recently proposed slanted grating couplers (SGCs) that operates in the strong coupling regime. Based on rigorous analysis of SGC properties, this design process utilizes the k-vector diagram and a rigorous grating leaky-mode solver to intentionally enforce the phase-match and Bragg conditions. We demonstrate that the resultant SGC designs have p...

This finite-difference time domain (FDTD) model for sound propagation in very shallow water uses pressure and velocity grids with both 3-dimensional Cartesian and 2-dimensional cylindrical implementations. Parameters, including water and sediment properties, can vary in each dimension. Steady-state and transient signals from discrete and distributed sources, such as the surface of a vibrating p...

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...

Abslrczc-The 3-dimensional finite-difference time-domain method in non-orthogonal co-ordinates (non-standard FDTD) is used to calculate the frequencies of resonators. The numerical boundary conditions of the method are presented. The influences of boundary conditions and discrete meshes on the numerical accuracy are investigated. We present the nonstandard FDTD method using the boundary-orthogo...

A grid resolution compensation scheme based on subgridding is proposed and evaluated for improving the performance of the finite-difference time-domain method implemented in cylindrical coordinates. The scheme introduces subgrids into the domain with smaller azimuthal grid spacings. This work investigates interpolation methods used for estimating unknown but required field values at the interfa...

Acceleration of FDTD (finite-difference time-domain) is very important for the fields such as computational electromagnetic simulation. We consider the FDTD simulation model of cylindrical resonator design that requires double precision floating-point and cannot be done using single precision. Conventional FDTD acceleration methods have a common problem of memorybandwidth limitation due to the ...

The finite-difference time-domain (FDTD) method is one of the most widely used computational methods in electromagnetic. This paper describes the design of two-dimensional (2D) FDTD simulation software for transverse magnetic (TM) polarization using Berenger's split-field perfectly matched layer (PML) formulation. The software is developed using Matlab programming language. Numerical examples v...

A. Trakic, H. Wang, F. Liu, H. S. Lopez, S. Crozier School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD, Australia Synopsis: Most Magnetic Resonance Imaging (MRI) spatial encoding techniques employ low-frequency pulsed magnetic field gradients that undesirably induce multi-exponentially decaying eddy currents in nearby conducting structures o...