Microwave characterization of ferrites

Summary form only given. The magnetic spectra of polycrystalline ferrites were examined. Ferrite electromagnetic properties may be anisotropic and nonlinear. In the presence of an externally applied DC-bias field or in the case of a significant internal anisotropy field, the behavior will be nonreciprocal, and the permeability must be described as a tensor rather than as a scalar. The authors emphasize the techniques by which accurate, constant-temperature complex permeability and permittivity measurements can be made, as well as the construction of physical models which spectrally characterize ferrite permeability variation. Magnetic loss mechanisms due to classical hysteresis, domain-wall motions, and gyromagnetic resonance were examined, and differential uncertainty analyses which treat sources of measurement error were performed.<>