A method of measuring the permittivity and/or conductivity of a multiphase fluid flowing through a conduit is provided. The method includes the steps of measuring the signal from a first electromagnetic transmitter to a first electromagnetic receiver separated by a first distance, measuring the signal from the first electromagnetic transmitter to a second electromagnetic receiver separated by a second distance, measuring the signal from a second electromagnetic transmitter to the first electromagnetic receiver separated by a distance substantially equal to the second distance, measuring the signal from the second electromagnetic transmitter to the second electromagnetic receiver separated by a distance substantially equal to the first distance, and wherein the first and second distances are substantially different. This is followed by the step of combining the four signals to obtain a measurement of the phase-shift and amplitude-attenuation substantially independent of the gain values applied to the receivers and transmitters to provide an estimate of the mixture permittivity and/or conductivity of the multiphase fluid.