De-embedding zero-field signal in high-frequency magneto-impedance measurements of soft ferromagnetic materials

Devices based on soft ferromagnetic materials are promising for high-frequency flexible electronics. Especially, wide-range tunable ferromagnetic resonance response of ferromagnetic microwires and ribbons can be functionalized in the form of magneto-impedance sensors in stretchable, bendable and twistable environments. A vector network analyzer calibrated by standard techniques is required to characterize the high-frequency properties of such devices. However, most of the calibration techniques necessitate calculations, computer simulations, and/or fabricating calibration kits in the shape of various test fixtures. Here, we employ a fixture calibration method for high-frequency (up to 4 GHz) impedance measurements of CoFeSiB microwires and melt-spun ribbons taking zero applied magnetic field as the reference. This method is based on a virtual de-embedding procedure, in which a reference signal is subtracted from all the subsequent measurements, which reduces the time for the total calibration procedure down to few minutes. Applications of the method are not limited to the cases where applied magnetic field varies. Any external parameter (strain, temperature, pressure etc.) that can change the impedance is allowed by this method.