  In this paper we are concerned with the plane wave method for the
discretization of time-harmonic Maxwell's equations in three dimensions. As
pointed out in [6], it is difficult to derive a satisfactory L2 error estimate
of the standard plane wave approximation of the time-harmonic Maxwell's
equations. We propose a variant of the plane wave least squares (PWLS) method
and show that the new plane wave approximations possess the desired L2 error
estimate. Moreover, the numerical results indicate that the new approximations
have sightly smaller L2 errors than the standard plane wave approximations.
More importantly, the results are derived for more general models in layered
media.
