On physical limitations for broadband electromagnetic scattering --- high order spherical waves

In English Limitations on the scattering matrix are derived for a
wide class of objects, restricting their broadband interaction
with electromagnetic vector spherical waves in terms
of their size, shape and static material properties. In particular,
it is seen that the order of the dominating term
for electrically small objects increases with the order of
the spherical wave. The results are applicable to many
areas concerned with electromagnetic waves interacting
with matter. For instance, they open up a new approach
to derive bounds on antenna performance. They can also
be generalized to acoustic and elastodynamic scattering.
Two intermediate results presented are a set of sum rules
for and the low-frequency asymptotic expansions of the
scattering and transition matrices of a general scatterer.