MEASUREMENT OF COMPLEX PERMEABILITY IN THE RF BAND
Rastislav Dosoudil – Vladimír Olah
The short circuit (coaxial transmission line) method has been used to determine the complex permeability of NiZnCu spinel ferrite and its composite material based on this ferrite (in the powder form) and a non-magnetic PVC polymer matrix over the frequency range 1 MHz to 1 GHz. We also report here on the design and verification of a simple high frequency coaxial line sample holder. The measurement principle as well as calibration and compensation procedures are discussed in detail. Impedance measurements were optimised by the partial elimination of undesirable influences. The measured values of impedances were recalculated to the equivalent values of complex relative permeability according to proposed formulas and the obtained results have been discussed. A user-friendly program written in VEE environment (Agilent technology) is provided for computer control and measurement process.
Keywords: complex permeability, short circuit method, sintered ferrite, ferrite polymer composite, impedance measurement