A New Shorted Microstrip Method to Determine the Complex Permeability of Thin Films

A new method is proposed to determine the complex permeability of ferromagnetic thin films from 100 MHz to 15 GHz. In this method, shorted microstrip transmission-line perturbation combined with the conformal mapping method is used. In contrast with previous methods to measure the thin films deposited on rigid substrates, this method neither requires any reference sample for calibration, nor requires the additional measurement to determine saturation magnetization. To assess the validity of this new method, three samples with different thicknesses are measured; comparisons are performed between the theoretical and experimental results, and the repeatability of this method is studied by measuring the samples five times. The results show that the complex permeability of ferromagnetic thin films can be measured within 10% errors.