Detection of high-frequency magnetic fields by a GMI probe

A giant magnetoimpedance (GMI) probe was fabricated in order to detect high-frequency magnetic fields. Magnetic near field measurements were carried out using the probe. A microstrip line driven by a current whose frequency was changed from 500 Hz to 1 GHz was used as a signal source in the measurements. The probe could clearly detect the characteristics of the field distribution such as high magnetic field strengths near both longitudinal edges of the signal plane of the microstrip line and null points. At a signal frequency of 100 MHz, the experimental result was compared with numerical calculation data. The output profile of the measurement agreed well with the profile of the calculated field distribution. The detection of the characteristics and the agreement indicate the potential that the GMI probe has high spatial resolution in a wide frequency range.