Low frequency (100 kHz–1 MHz) permeability measurement method in magnetic material

A low frequency (100 KHz~1 MHz, mainly use in magnetic resonance wireless power transfer system ) permeability measurement method is designed and tested in this paper. In this method, a coaxial cavity and a low frequency band (30 KHz~8 GHz) Vector Network Analyzer (VNA) are used as measurement equipment. Comparing the impedance change of coaxial cavity, with magnetic material in it or with air, we can calculate the permeability of the magnetic material. This is a mature method of low frequency permeability measurement. The original measurement method is well developed while has a critical disadvantage in previous works. It is because that the equipment will bring in a strong nonlinearity error and cause the measurement data inaccuracy when the measurement frequency is as lower as VNA work range. Our sample work is attempting to modify the nonlinearity error and attain more accuracy test data. Compared with professional Impedance Analyzer, this measurement method takes lower costs and obtains more accurate permeability parameter by common VNA equipment and corrected data respectively.