Changes

where i, j, k are the grid position indices along the X, Y, Z axes and n is the current time step. Similar expressions are obtained for the Y and Z components of the electric and magnetic fields. When your physical structure involves lossy materials with nonzero electric conductivity σ and/or nonzero electric conductivity σ_m, the above update equations become more complicated. In the case of anisotropic materials with tensorial constitutive parameters, the electric displacement vector D and magnetic induction vector B need to be involved in the update of Maxwell's equations at every time step. This results in a total of twelve update equations at every time step. In the case of dispersive materials with time-varying constitutive parameters, additional auxiliary differential equations are invoked and updated at every time step. Applying the proper boundary conditions for all the materials inside the computational domain and at the boundaries of the domain itself, EM.Cube calculates and "updates" all the necessary field components at every mesh node, at every time step. The time marching loop continues in this way until it is terminated based on a certain criterion.

The FDTD method provides a wideband simulation of your physical structure. Frequency domain techniques often require a tedious frequency sweep to calculate the port characteristics (S/Y/Z parameters). By contrast, EM.Cube's [[FDTD Module]] performs a discrete Fourier transform (DFT) of the time domain data to calculate these characteristics at the end of a single FDTD simulation run. In order to produce sufficient spectral information, an appropriate wideband temporal waveform is needed to excite the physical structure. The general form of EM.Cube's default excitation waveform is a Modulated Gaussian Pulse given by: