Approximate Equations for the Reflection Coefficient from a Homogeneous Quarter-Wavelength Radar Absorbing Layer

A theoretical and numerical investigation of the quality criteria for radar absorbing coatings (RACs) has been conducted. Simple analytical expressions for the minimum of the reflection coefficient of a homogeneous absorbing layer have been obtained. It is shown that this value is not a correct characteristic of radar absorption. To describe the quality of RACs, it is necessary to use either the relative bandwidth of its operating waveband or the ratio of the operating waveband to the layer’s thickness. The former of these quantities may be useful when it is important to achieve a high broadband absorbency, while the latter is useful for achieving a small thickness of an absorber.