Propagation through simple window frame structures at outdoor/indoor interface

This paper investigates propagation feature through window frame structure at outdoor/ indoor interface environment. As a simple window frame structure, we consider wide aperture slits in an infinitely long PEC screen. High frequency asymptotic analysis with the ray-mode coupling technique is applied to derive the diffracted fields. The analysis for single slit is extended to that for double slits problem. It is confirmed from the detailed considerations that the present ray solution can be confidently utilized even when the distance of adjacent slits is relatively small.