  In this work it is investigated, in the parallel-plate waveguide case, how
the 1D, 2D or 3D motion of the electrons inside the waveguide can affect the
generalized susceptibility diagrams, by means of a developed model capable of
tracking the exact trajectory of multiple effective electrons which includes
effects such as the spreading of the secondary electron departure kinetic
energies or the dependence on elastic and inelastic electrons. On the other
hand, a comparative study of the susceptibility charts in a parallel-plate and
in its equivalent rectangular waveguide with the same height is performed,
showing how the inhomogeneity of the electric field inside the waveguide
modifies the multipactor region with respect to that predicted by the
parallel-plate waveguide case. The results of this study are going to be
extended to a partially dielectric-loaded rectangular waveguide, which is a
problem of great interest in the space industry that has not yet been
rigorously investigated in the literature.
