A Water-Based Conical Blackbody Concept for Millimeter-Wave Remote Sensing

We propose a novel concept for water-based blackbodies to be used as calibration sources in microwave remote sensing instruments. In order to obtain a low electromagnetic reflectivity, a curved conical interface between water and air has been developed by means of numerical simulations. A blackbody prototype consisting of a 3D printed conical low-loss plastic shell was manufactured and experimental results demonstrate that the reflectivity of the proposed prototype is superior to established blackbody concepts. In particular, the S-11 is below -60 dB in the considered frequency ranges between 150 and 400 GHz.