A Two Dimensional Linear Bicharacteristic Scheme For Electromagnetics

A Two-Dimensional Linear Bicharacteristic Scheme for Electromagnetics

A Two-Dimensional Linear Bicharacteristic Scheme for Electromagnetics

The upwind leapfrog or Linear Bicharacteristic Scheme (LBS) has previously been implemented and demonstrated on one-dimensional electromagnetic wave propagation problems. This memorandum extends the Linear Bicharacteristic Scheme for computational electromagnetics to model lossy dielectric and magnetic materials and perfect electrical conductors in two dimensions. This is accomplished by proper implementation of the LBS for homogeneous lossy dielectric and magnetic media and for perfect electrical conductors. Both the Transverse Electric and Transverse Magnetic polarizations are considered. Computational requirements and a Fourier analysis are also discussed. Heterogeneous media are modeled through implementation of surface boundary conditions and no special extrapolations or interpolations at dielectric material boundaries are required. Results are presented for two-dimensional model problems on uniform grids, and the Finite Difference Time Domain (FDTD) algorithm is chosen as a convenient reference algorithm for comparison. The results demonstrate that the two-dimensional explicit LBS is a dissipation-free, second-order accurate algorithm which uses a smaller stencil than the FDTD algorithm, yet it has less phase velocity error.Beggs, John H.Langley Research CenterELECTROMAGNETIC WAVE TRANSMISSION; COMPUTATIONAL ELECTROMAGNETICS; METHOD OF CHARACTERISTICS; TRANSMISSION LOSS; UPWIND SCHEMES (MATHEMATICS); PERFECTLY MATCHED LAYERS; FINITE DIFFERENCE TIME DOMAIN METHOD; TWO DIMENSIONAL MODELS; LOSSY MEDIA; DIELECTRICS; ELECTROMAGNETISM; PHASE VELOCITY

The Linear Bicharacteristic Scheme for Electromagnetics

This report extends the Linear Bicharacteristic Scheme for computational electrommagnetics to model lossy dielectric and magnetic materials and perfect electrical conductors. This is accomplished by proper implementation of the LBS for homogeneous lossy dielectric and magnetic media and for perfect electrical conductors. Heterogeneous media are modeled through implementation of surface boundary conditions and no special extrapolations or interpolations at dielectric material boundaries are required. Results are presented for one-dimensional model problems on both uniform and nonuniform grids, and the FDTD algorithm is chosen as a convenient reference algorithm for comparison. The results demonstrate that the explicit LBS is a dissipation-free, second order accurate algorithm which uses a smaller stencil than the FDTD algorithm, yet it has approximately one-third the phase velocity error. The LBS is also more accurate on nonuniform grids.