Loaded epoxy for microwave applications

Radio-frequency and microwave applications often require castable absorbers with well known electromagnetic properties. In this context, we fabricated and characterized a few samples using different ratios of a commercially available epoxy (Stycast 2850FT) mixed with commercially available metal powders. We performed transmission measurements from 7 GHz up to 170 GHz using a VNA and a series of standard horns antenna. Then we used an empirical formula to extract complex permittivity and permeability and reflection measurements to validate the results. For a final cross-check we used capacity measurements to find the DC permittivity of our samples and compared the results with the value extracted from our previous analysis. We present analysis method, parameter extraction pipeline and results for different samples with different powders and epoxy-powder mass ratios.