Approximate full wave method for electromagnetic analysis of thick apertures

An approximate full-wave method for the electromagnetic analysis of thick apertures is presented. The method has the great advantage of not increasing the computational burden with respect to the zero-thickness case. At the same time, the hindrance of evaluating the cavity Green's function for arbitrary shaped structures is avoided. The method shows good results when compared to the full-wave cavity analysis of apertures in metallic screens of practical thicknesses up to /spl lambda//10.