Calculating Shielding Loss Due to a Gap between Radio Wave Shield Concrete Walls

In a radio-wave shield, a method of blocking radio waves in which a space is surrounded by a high loss dielectric material, some waves leak through the long and slender gap between the walls. We analyzed the losses in the gap section and in the gap aperture. The former was analyzed by using an equivalent parallel board transmission line, the latter by using an aperture field method. Here we describe these analyses and the experimental support of the results.