Method when measuring the properties of a material by a microwave-frequency measuring procedure to compensate for the influence of random variations in the mutual position of the antennas and the material on the measurement result

摘要

There is described a method for measuring of properties of a material by using microwave energy, which is directed against the material and detected after its passage through and/or reflection against the material. To compensate for the perturbing influence on the measurement result that can be produced by variations in the position of the material relative to the microwave antennas used, especially when the measurement occurs on a material which can move during the measurement, two separate measurement channels with essentially the same frequency are used, wherein the sending and receiving antennas for these two measurement channels are arranged at somewhat different positions relative to the material in such a way that when the position of the material varies, a signal change occurring in one measurement channel, such as that caused by interference, corresponds to an oppositely directed change in the signal in the other measurement channel, so that a mean value, possibly weighted, of the measurement signals from the two channels will be essentially unaffected by variations in the position of the material relative to the sending and receiving antennas. IMAGE