Uncertainty analysis of measurement of complex dielectric permittivity using microstrip transmission line

Microstrip transmission line shows many properties which make it well suited as a medium for complex dielectric permittivity measurement. Such a system could be based on determining the effective permittivity of a microstrip line covered by an unknown dielectric substance. Simple approximate expressions for the effective permittivity are compared with a more rigorous (and hence more computationally involved) solution in order to gain some insight into the accuracy of the approximate solutions with respect to the dielectric material covering the microstrip line. Experimentally determined values of effective permittivity for various standard organic liquids are also presented for comparison.