Eliminating the ambiguity in nonperturbation microwave measurements of permittivity

The authors propose a method for eliminating the ambiguity in the dielectric constant which appears in many measurement techniques at microwave frequencies. They describe the procedure in a general way and apply it to the TE cavity technique to measure the permittivity of liquids and to the short-circuited line technique. The viability of the procedure and its simplicity compared with commonly used methods are shown. Complicated calculations involved in the comparison of two sets of solutions of two transcendental equations are avoided, and the correct value of the dielectric constant is obtained from the root of a simple algebraic equation