抄録
It is important to grasp the reflectivity of EM wave absorbers in millimeter waves by rapid progress in a recent utilization of the frequency. A Free Space Method with horn antennas is in widespread use for the reflectivity evaluation of EM wave absorbers. In this paper, we investigate a Free Space Method that can evaluate accurately the reflectivity of EM absorbers in millimeter waves. We present the fundamental data and conditions for a Free Space Method to evaluate accurately the reflectivity of EM absorbers in millimeter wave. Moreover, the reflectivity of dielectric materials (e.g., quartz glass, single crystal sapphire) with a uniform constant is measured. As a result, the validity of a Free Space Method in millimeter waves is confirmed by comparing the evaluated characteristics of dielectric materials to a theoretical value.
