DETERMINATION OF PERMEABILITY FROM IMPEDANCE MEASUREMENT USING VECTOR NETWORK ANALYSER

Rastislav Dosoudil

   This study treats the optimised one-port (reflection coefficient) and two-port (shunt-through/series-through) measurement methods for complex permeability determination of solid soft magnetic materials using a vector network analyzer (VNA) at fre-quencies from 9 kHz to 6.5 GHz. The principle of measurement methods, the relationships of measured phasor voltage ratio (S-parameter) to complex impedance, and permeability calculation equations are presented. Each method gives good measurement sensitivity at the impedance range where the measured ac voltage at the VNA’s receiver significantly varies. For permeability evaluation, the shunt-through method provides the best sensitivity and stability and thus is suitable for both low and high perme-ability materials.

Keywords: impedance, permeability, network analyzer, measurement, scattering parameter

[full-paper]