Simultaneous Evaluation of Permeability and Permittivity using a Flexible Microstrip Line-Type Probe up to 67 GHz

Complex relative permeability and permittivity were evaluated simultaneously in the band of 100 MHz–67 GHz using a flexible microstrip line-type probe. In principle, the probe can evaluate the permeability and permittivity of electromagnetic materials regardless of size. The measured permeability and permittivity were obtained from the transmission coefficient (S21). Since S21 under the infinite magnetic field can be estimated by changing the DC magnetic field stepwise, the magnetic and dielectric signals were separated accurately. The complex permeability and permittivity of an NiZn ferrite sheet (10 mm × 10 mm, 0.1 mm thick) and polytetrafluoroethylene (PTFE) (25 mm × 25 mm, 0.79 mm thick) were evaluated accurately.