Analysis of finite grid structures with lenses in quasi-optical systems

A full-wave moment-method technique developed for the analysts of quasi-optical (QO) systems is used to model finite grid structures in a lens system. This technique incorporates an electric-field dyadic Green's function for a grid centered between two lenses. This is derived by separately considering paraxial and nonparaxial fields. Results for the driving point reflection coefficient of a 3/spl times/3 and 5/spl times/5 grid in the lens system are computed and compared with measurements.