Fields Monitoring
The time domain field monitoring is very useful and flexible but is most informative with a sinusoidal excitation at a particular frequency. Thus one frequency can be thoroughly investigated at a time.
QuickWave enables another useful feature, which allows watching the field distribution at selected frequencies from data extracted by Fourier transforming of the results of simulation obtained with pulse excitation. Thus we obtain the frequency domain fields from the time domain ones via Fourier transform. Such a post-processing is called FD-Monitors and may be described as a frequency domain monitors (FDM). It performs Fourier-transformation of the field components chosen from the selection of: Ex, Ey, Ez, Hx, Hy, Hz, at frequencies and volume specified by the user.
The FD-Monitors post-processing delivers the following results:
•
magnitude, real and imaginary parts of the selected field components
•
real and imaginary parts of total electric and magnetic field
•
real and imaginary parts of the Poynting vector
•
magnitude of the dissipated power and dissipated power density
It is worth noting at this point that in the Fields Monitor window of QW-Simulator, the user is provided with the distribution of the field amplitudes (real, and imaginary parts or absolute values) for the considered frequency, as the FD-Monitors post-processing results, but he can also monitor the field components in time via Animation feature. The animation of fields takes into account the amplitudes and phase relations calculated from FD-Monitors post-processing. Let us note here that the time variation here is based on a different principle than when we watch the fields concurrently with FDTD simulation. Here we use the field amplitude and phase obtained for a particular frequency through a Fourier transformation of the time-domain signals during FDTD simulation and reproduce them in artificial time not synchronized with the time of FDTD simulations.
