Wave Mechanics of Microwave Absorption in Films: Multilayered Films

In the field of microwave absorption, the quarter-wavelength theory (QWM) is commonly employed to describe the properties of films with multiple layers. However, this study demonstrates the inadequacy of QWM as conventional results pertaining to single-layered films with or without a metal backing are typically applied to the intermediate layers of multilayer films, but that approach is flawed, as it overlooks the presence of incident microwaves on both sides of the intermediate layer, focusing solely on those in front of the film. To address this notable omission, a novel theoretical framework suitable for multilayer films is introduced and validated.