IMPROVEMENT OF THE TRANSMISSION REFLECTION METHOD FOR DIELECTRIC AND MAGNETIC MEASUREMENTS ON LIQUIDS BETWEEN 0.1 AND 20 GHZ

We propose an appropriate calculation method, giving both the complex permittivity epsilon and permeability mu* of a liquid sample, from tr ansmission/reflection measurements obtained from a network analyser wo rking on a coaxial line between 0.1 and 20 GHz. A 20 mm long specific coaxial cell has been constructed using two polytetrafluoroethylene jo ints to ensure air tightness. Its small length allows rejection toward s the upper frequencies of the measurement anomalies given by the Nico lson-Ross equations. Positions and thickness of the joints are taken i nto account by the calculus. The whole system has been tested with the empty cell and then on several alcohols and ferrofluids. The results on alcohols are in excellent agreement with all previous results; meas urement on one of the magnetic fluids (Fe2MnO4 in CCl4) has shown a Ne el relaxation and also a gyromagnetic resonance.