L. A. Kunyansky and O. P. Bruno
On the validity of two-face equivalent source approximations
(255K, Postrscript)

ABSTRACT.  A family of fast surface scattering solvers developed recently 
is based on approximation of the surface field by the 
field of so-called equivalent sources. Use of certain spatially 
sparse distributions of equivalent sources is advantageous for 
reducing the operation count of the algorithms. It turns out, 
however, that certain types of sparse distributions cannot produce 
the required approximations. In the present work we prove that use 
of the so-called two-face source distributions of equivalent sources 
is indeed sufficient to produce approximations of required accuracy.