The invention relates to devices comprising field effect transistors to detect the power of an electromagnetic high frequency signal VRF. According to the prior art, the high frequency signal is coupled into the gate G and via a capacitor CGD into the drain D of the field effect transistor FET, the gate G being biased with a direct voltage Vg which corresponds to the threshold value of the FET transistor. The resulting current at the source S contains a direct current portion Ids which is proportional to the square of the amplitude of the high frequency signal. The operating frequency of said power detectors is limited to a few gigahertz (GHz) by the discrete arrangement and especially by the predetermined gate length of the field effect transistor. The aim of the invention is to improve a resistive mixer in such a manner that it can be operated at high gigahertz and terahertz frequencies. For this purpose, the resistive mixer comprises a line which has a first and a second electrical conductor having respective connecting contacts so that an electrical high frequency signal can be coupled into the line, the first conductor having a plurality of series-connected voltage-dependent resistor elements (R) and at least one capacitive element (C) being interposed between the first and the second conductor.