A device for power measurement for the purposes of plausibility checking andor calibration of a primary power measurement device on a power amplifier of a magnetic resonance device is provided. One or more of the transmissions are made as transmission shafts from a material containing titanium or include a material containing titanium. Techniques for filling pores of such glass structure with a material having a high refractive index, and for then removing the glass structure. Using the determined horizontal resistivities and another subset of the multi-component measurements, the vertical resistivities are obtained.