Multi-frequency resonant measurements of the complex permittivity and initial permeability of barium ferrite ceramic

The complex permittivity and complex initial permeability of barium ferrite ceramic rods have been measured at multiple frequencies in the 4-18 GHz range employing a cylindrical TM0n0 mode cavity and five different TE011 dielectric resonators. The imaginary parts were found to be in the 10-4 – 10-3 range, which is much lower than those given in literature data, apparently due to limited resolution of transmission/reflection methods. The obtained results are well-described by a two-resonance permeability model.