Broad-band measurements of complex permittivity using coaxial discontinuities with non-uniform cross-section

This paper proposes a new broadband measurement technique for the parameter extraction of permittivity using a class of coaxial discontinuities. The material under test may be radially coated on the inner conductor or may be placed in the vicinity of the outer conductor. Experiments have been done with an APC7 coaxial cell together with a network analyzer for different liquid materials. The coating thickness, that is controllable, can be chosen to ensure a high precision of the S-parameters. These S-parameters were measured from 1 through 18 GHz and they show a good agreement with theoretical results predicted by a frequency-domain TLM algorithm