  In this article, we analyze the microlocal properties of the linearized
forward scattering operator $F$ and the normal operator $F^{*}F$ (where $F^{*}$
is the $L^{2}$ adjoint of $F$) which arises in Synthetic Aperture Radar imaging
for the common midpoint acquisition geometry. When $F^{*}$ is applied to the
scattered data, artifacts appear. We show that $F^{*}F$ can be decomposed as a
sum of four operators, each belonging to a class of distributions associated to
two cleanly intersecting Lagrangians, $I^{p,l} (\Lambda_0, \Lambda_1)$, thereby
explaining the latter artifacts.
