Abstract
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 therein conventional results pertaining to single
layered films with or without a metal backing are typically applied to the intermediate layers
of multilayer films, but this 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, our work introduces a novel theoretical framework
suitable for multilayer films