PROCEDURE FOR ACCURATE AND STABLE CONSTITUTIVE PARAMETERS EXTRACTION OF MATERIALS AT MICROWAVE FREQUENCIES

A non-resonant microwave method has been proposed for accurate and stable constitutive parameter measurement of low-loss dispersive and non-dispersive isotropic materials. The method uses transmission-only measurements of two conflgurations: a) the sample inside a sample holder and b) the sample backed by a reference sample inside the same holder. It is not prone to undesired ripples in the extracted constitutive parameters arising from measured similar re∞ection properties. In addition, its accuracy is higher since it is not much afiected by surface roughness and/or unevenness of the sample or the reference sample. It is based on frequency-by-frequency extraction and thus suitable for dispersive materials. However, it requires the selection of an appropriate reference sample. The method has been validated by measurements at X-band (8.2{12.4GHz) of a low-loss sample located into a waveguide sample holder.