Device for measuring the dielectric and/or magnetic properties of a sample by means of a microwave transmission measurement, said device comprising: a transmitting antenna and a receiving antenna which define a transmission measuring section in which the sample to be measured can be positioned; a transmitting module comprising two transmitting-side synthesizers (12, 14) each for generating a high-frequency signal (F1, F2) with a frequency between 800MHz and 30GHz and a transmitting-side mixer; a frequency normal connected to the transmitting-side synthesizers (12, 14) via a transmitting-side low-frequency synchronization signal line, to which frequency normal the transmitting-side synthesizers (12, 14) are coupled phase-locked reproducible, and an evaluation unit being connected to the transmitting-side synthesizers (12, 14) and to the receiving antenna at least indirectly, wherein the device is configured to supply the high-frequency signals (F1, F2) of the transmitting-side synthesizers (12, 14) to the transmitting-side mixer, to supply the intermediate-frequency signal, which is generated by the transmitting-side mixer from the two high-frequency signals (F1, F2) to the evaluation unit, and to supply the high frequency of the first transmitting-side synthesizer to the transmitting antenna, wherein additionally a receiving module which is spatially remote from the transmitting module is provided, said receiving module comprising a receiving-side synthesizer and a receiving-side mixer, wherein the receiving-side synthesizer is connected to the frequency normal via a receiving-side low-frequency synchronization signal line and is coupled thereto phase-locked reproducible and is additionally coupled to the evaluation unit at least indirectly, and wherein the device is configured to supply the high-frequency signal (F1') received by the receiving antenna and the high-frequency signal generated by the receiving-side synthesizer to the receiving-side mixer, to supply the intermediate-frequency signal generated by the receiving-side mixer from the two high-frequency signals to the evaluation unit, wherein the second transmitting-side synthesizer and the receiving-side synthesizer are configured to generate the same high frequency, and the first transmitting-side synthesizer is configured to generate a high frequency that differs therefrom. a transmitting antenna and a receiving antenna which define a transmission measuring section in which the sample to be measured can be positioned; a transmitting module comprising two transmitting-side synthesizers (12, 14) each for generating a high-frequency signal (F1, F2) with a frequency between 800MHz and 30GHz and a transmitting-side mixer; a frequency normal connected to the transmitting-side synthesizers (12, 14) via a transmitting-side low-frequency synchronization signal line, to which frequency normal the transmitting-side synthesizers (12, 14) are coupled phase-locked reproducible, and an evaluation unit being connected to the transmitting-side synthesizers (12, 14) and to the receiving antenna at least indirectly, wherein the device is configured to supply the high-frequency signals (F1, F2) of the transmitting-side synthesizers (12, 14) to the transmitting-side mixer, to supply the intermediate-frequency signal, which is generated by the transmitting-side mixer from the two high-frequency signals (F1, F2) to the evaluation unit, and to supply the high frequency of the first transmitting-side synthesizer to the transmitting antenna, wherein additionally a receiving module which is spatially remote from the transmitting module is provided, said receiving module comprising a receiving-side synthesizer and a receiving-side mixer, wherein the receiving-side synthesizer is connected to the frequency normal via a receiving-side low-frequency synchronization signal line and is coupled thereto phase-locked reproducible and is additionally coupled to the evaluation unit at least indirectly, and wherein the device is configured to supply the high-frequency signal (F1') received by the receiving antenna and the high-frequency signal generated by the receiving-side synthesizer to the receiving-side mixer, to supply the intermediate-frequency signal generated by the receiving-side mixer from the two high-frequency signals to the evaluation unit, wherein the second transmitting-side synthesizer and the receiving-side synthesizer are configured to generate the same high frequency, and the first transmitting-side synthesizer is configured to generate a high frequency that differs therefrom.