Akademik Veri Yönetim Sistemi
JOURNAL OF PHYSICS D-APPLIED PHYSICS, cilt.42, sa.7, 2009 (SCI-Expanded)
Calibration-independent microwave methods have successfully been used to determine the complex permittivity, e, of dielectric materials by eliminating the necessity of the calibration before measurements. However, there are three main problems of these methods. These are: (a) they suffer from thickness uncertainty in the second sample for methods which utilize propagation constant measurements, (b) they require precise or exact shifting distance of the sample within its cell location (a waveguide or coaxial-line section) and (c) they may produce some singularity points in the measured e. In this paper, we propose a new calibration-independent method which simultaneously eliminates all these drawbacks while extracting the nonsingular complex permittivity of solid materials. We use the uncalibrated scattering parameter measurements of the cell with the dielectric sample located arbitrarily and of extra cells attached to the same cell to achieve this goal. In addition, in the literature, there is a need for a technique which auto-monitors the accurateness of calibration-independent measurements, which are used for the extraction of electrical properties of materials. In this paper, we also propose a simple self-checking technique, which is independent of electrical properties and thickness of materials and the location of materials inside the measurement cell. Therefore, this technique gives information about the performance of measurements before extracting electrical properties of materials. We validate the proposed method by measurements of the e of polyvinyl-chloride (PVC) and Plexiglas samples at X-band (8.2-12.4 GHz)