Determination of the magnetic fluid parameters from the microwave radiation reflection coefficients

Abstract

The interaction of microwave radiation with a magnetic fluid that completely fills a waveguide and is bounded by a dielectric insertion is studied at frequencies between 20 and 40 GHz. The frequency dependence of the alternating interference maxima and minima that are associated with the reflection from the front and back walls of the dielectric insertion is found. The reason for such a dependence is the variation of the complex magnetic susceptibility of the magnetic fluid. The inverse problem, i.e., the determination of the ferromagnetic particle diameter and the volume content of the solid phase in the magnetic fluid, is solved based on the frequency dependence of the reflection coefficient.