A formal solution to the scattered field of a particle of arbitrary sh
ape and optical constants located on or near a perfectly conducting su
rface is derived. The solution is in terms of a vector harmonic expans
ion. The only knowledge required of the particle is its scattering coe
fficients when the plane surface is not present. It is sufficiently ge
neral that the particle can be inhomogeneous or represent a set of sub
particles.