Public reporting burapn lor thi% collection o' information i% estimated to a»«rage i hour per response, inclu gathering jnd maintaining the data needed, .ind completing and reviewing the collection of mCormatiOn S« collection of intonation, including *uggnttont for reducing trm txirden. lo wva*h«r*gton Headquarter* SerOavu Highway. Su»te 120*. Arlington, va 22202-J 302. and to the Office o' Management sod Budget. Paperv APRL-SR-BL-TR-01- PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES)Cambridge Hydrodynamics, Inc. P.O. Box 1403 Princeton NJ 08742 SPONSORING /MONITORING AGENCY NAME(S) AND ADDRESS(ES)Air The scattering of electromagnetic waves from complex object coated with lossy materials with negative and positive permitivity embedded in a layered medium is analysed via a new formulation, and a new set of algorithms to implement these formulations is introduced. This new technology is applied here to phase shifted photomasks. The results for various wavelengths and mask thicknesses have been considered carefully and are reported here.