Quasi-PML for waves in cylindrical coordinates

A nonuniform cylindrical FDTD algorithm with improved PML and quasi-PML absorbing boundary conditions

“…Although it can be shown that QPML does not give a perfect absorption [27], practically we are able to make the reflection from the QPML ABC small enough. Recently, Chew et al have proposed a complex coordinate system for the development of a true PML ABC for cylindrical and spherical coordinates [28].…”

“…Although it can be shown theoretically that this PML is not perfectly matched (thus the name quasi-PML) [27], practically it provides a satisfactory ABC with a 20% saving in computer memory and computation time compared with the improved true PML (CPML) scheme.…”

“…The reflection is about 1.1% and 0.91% for QPML and CPML, respectively. Note that for a fair comparison, we have chosen in the QPML case even though the code allows a profile for As discussed below, this reflection can be reduced substantially by adjusting It is worthwhile to point out that, as the radius of the truncating boundary increases, the difference between the QPML and CPML diminishes [27].…”

Efficient Computation of Electromagnetic Waves in Anisotropic Orthogonal-Plano-Cylindrically Layered Media Using the Improved Numerical Mode Matching (NMM) Method

“…It provides a robust way to calculate the field in lossless or low-loss media, and greatly reduce the number of elements for very lossy media. By using the stretched-coordinate system [23]- [27], the permittivity and permeability in the PML can be easily chosen as:…”

“…The real and imaginary parts of e ρ and e z should be sophistically chosen to optimize the computational time and accuracy. Second order polynomial profile is employed in our simulation as references [19], [24]- [27]. For the ρ direction,…”