A Microwave Method for Noniterative Constitutive Parameters Determination of Thin Low-Loss or Lossy Materials

A noniterative transmission-reflection method is proposed for instant measurement of constitutive parameters of thin samples attached to a sample holder. It uses reflection-only measurements for constitutive parameters determination thanks to the asymmetric nature of the structure (holder sample). In addition, the method can also measure the complex permittivity of the sample holder from transmission and reflection measurements. The disadvantage of the method, however, is that it requires different reflection-only measurements, and hence, a suitable selection of holder thickness and permittivity combination. In case similar reflection properties of the structure are measured, the noniteratively measured constitutive parameters by the proposed method can be utilized as an initial guess in a search algorithm, which uses transmission and reflection measurements. In this way, the proposed method provides a suitable initial guess for electrical properties of materials under test with no prior information.