Novel Microwave Resonant Technique for Accurate Testing of Magnetic Materials

A robust cavity technique is proposed to quite accurately measure the complex permeability of the magnetic materials, which gives promising results for arbitrary length samples. This technique takes into account many factors such as magnetic field correction inside the sample under test, the effect of demagnetization, and the image theory, which was not considered in past. In this paper, a numerical model of the magnetometric demagnetization factor is developed, which precisely considers the effects of the relative permeability of sample and the nonuniform magnetic field over sample volume. The sensitivity of proposed technique is better than conventional and recently modified technique assuming arbitrary length sample. The proposed scheme typically provides 98% accurate result for the sample length greater than 0.15× the width of the rectangular cavity. The proposed method is quite novel and can be appreciated due to the fact that it gives higher accuracy for all the cases when compared with other standard cavity techniques.