Circular waveguide method for measuring reflection properties of absorber panels

A technique is developed for direct determination of the plane wave reflection properties of plane layered media. The approach is applicable for media containing a high-index absorber layer. A circular waveguide aperture is used to measure the near field scattering from the external medium. The analytical development results in a set of Smith chart contours from which the reflection properties of the medium can be determined from the measured waveguide reflection coefficient. The approach is demonstrated with measurements of a ferrite absorber panel.