Scalar permeability measurements of microwave ferrites using lumped circuit, coaxial line, and resonance techniques

Complex scalar permeability measurement results of microwave ferrites at frequencies from 1 Hz to 20 GHz are presented. Three different techniques were used to perform the measurements. The method chosen depended on frequency and magnetic loss. At low frequencies, 1-10 ⁵ Hz, we applied lumped parameter circuit techniques. With this technique nonlinear permeability effects were measured. At higher frequencies, from 1 MHz up to gyromagnetic resonance, coaxial transmission line techniques were used. At frequencies above gyromagnetic resonance, a dielectric ring resonator technique was used. By combining all three methods, the real and imaginary parts of sample permeability, with magnetic loss factors that vary from 10^-5 to 10², may be measured. In addition, nonlinear effects in ferrite materials and saturation magnetization may be evaluated