In this work, the inverse boundary value problem for Maxwell's equatio
ns is considered. The objective is to estimate the electric permittivi
ty and conductivity as well as the magnetic permeability within a body
from stationary high-frequency field measurements on the boundary of
the body. A layer-stripping algorithm for estimating the parameters in
the body can be described as follows. First, the unknown parameters a
re estimated at the boundary of the body by applying highly oscillatin
g field excitations. Then the surface data are propagated through the
estimated surface layer by an invariant embedding equation. Repeating
the process, one 'peels off' the body layer by layer. The aim of this
article is to show that the necessary tools for the algorithm applied
to Maxwell's equations exist. A propagation equation for the boundary
data is derived and it is shown that measurements with high spatial va
riations give an estimate for the unknown material parameters at the b
oundary. Due to the energy dissipation, the method is expected to work
near the boundary of the body.