The animation is meant to illustrate the periodic power transfer between
two adjacent, evanescently coupled parallel waveguides. The frames show the
local intensity
on cross section planes (the black lines indicate the permittivity
boundaries) at different positions on the propagation axis.
Note that this concerns stationary fields;
the time coordinate of the animation replaces the propagation distance.
The gif-image was generated via MATLAB by the direct m-file output of the
WMM programs. See the
WMM-Manual
for a detailed description.