A new short-circuited coplanar waveguide to measuring the permeability of magnetic thin film: Comparison with short-circuited microstrip line

Abstract

Recently, soft magnetic thin films with high complex permeability μ, which can be used in the devices working at GHz range, have drew great attentions. A reliable and authentic permeability is very important for their applications. Microwave complex permeability μ=μ'+jμ can be obtained by using the vector network analyzer (VNA). Generally, a jig was used to hold the magnetic thin films and detect their permeability spectra. The short-circuited microstrip line (MSL) was often as the preferred option because of its high sensitivity and other characteristics. [1] However, in some cases, the permeability measurements also require easy to operate the thin film in the jig. Two-port coplanar waveguide (CPW) was used to measure permeability due to its simple and open structure. [2] In this work, we proposed a short-circuited CPW jig, which can easy load the films and detect the permeability spectra. For comparison, short-circuited MSL is also used to measure permeability and the results are analyzed based on the Landau-Lifshitz-Gilbert (LLG) equation.