The Fe Micropowder Low-pass Coaxial Filter Tunable by Magnetic Field

In this paper, the behavior of the coaxial filter filled with carbonyl iron micropowder was studied. Amplitude-frequency characteristics (AFC) and phase-frequency characteristics (PFC) were obtained. Using the non-resonant technique value of the refractive index was measured. Moreover, with the same technique dependence of refractive index on the magnetic field was studied. It is discovered that such a filter has hysteresis losses. Furthermore, by varying the amplitude of the magnetic field one can change the AFC of the filter (i.e. cut off frequency).