A measurement method for the broad-band determination (100 MHz-10 GHz) of t
he permeability and permittivity of thin films with thicknesses of 1-10 mu
m has been developed. The technique is based on the measurement of the S pa
rameters of a microstrip line loaded with the test sample, The S parameters
are measured with a network analyzer. Besides its band width, the original
feature of this method in comparison with existing techniques lies in the
fact that the thin film does not entirely fill the cross section of the cel
l since it is directly laid on the substrate of the microstrip line. This l
eads to a simple and reproducible measurement process. It also permits the
propagation of the electromagnetic wave along the film width of about a few
millimeters, thus increasing the measurement accuracy. Moreover the method
remains reliable for the characterization of bulk materials with the same
cell and data processing program.