Microwave permittivity measurement of polymers by deposition on a coplanar wave guide

A balance is made between accuracy and cost in the wideband (45 MHz-18 GHz) determination of the permittivity of a polymerised elastic coating. It is shown that the combination of S-parameters measurements of 2 coplanar wave guides (CPW) before and after coating with a thick layer of the material under test (MUT) and the use of an analytical expression for the calculation of the permittivity of the lines, can lead to a 'best bargain' solution. Expensive narrow-banded methods fall out of the scope for this application.