Study On Swept-Frequency Measurement Of Complex Permittivity Based On Microwave Dielectric

As Mobile telecommunication devices or high-speed digital circuits are supported by many types of materials, there are increasing demands among manufactures for the determination of the materials' electromagnetic properties in microwave and millimeter-wave frequencies. Therefore it is crucial to study the dielectric properties of materials and the measurements of dielectric.Firstly, the conventional and common methods of dielectric measurements in microwave and millimeter-wave frequency have been reviewed in the present paper. Three methods is briefly mentioned, waveguide method, resonance method, free-space method. Compared with each method, the suitable applying situation and the advantage and disadvantage of each method have been acquired.Secondly, in view of the hybrid measuring system made up of VGA and waveguide, the terminal reflection method based on transmission line theory have been mentioned. Then the basic principle of the input impedance method is briefly stated in paper, and it is moreover the uppermost measurement applied to our most experiments of research.Thirdly, some common methods to solve complex polynomial and transcendental equation are mentioned, and two main numerical computation method are concretely presented. Then the concrete approach of input impedance method and its numerical computation of results are minutely related in the present paper.Fourthly, the scatter network measurement and the NRW T/R measurement have been discussed when it is turned into two port transmission network based on the waveguide. Then rectangular specimen has been changed into columnar specimen in experiments, and a new method based on this transformation is proposed, and moreover results are compared with the conventional transmission-line method. It is confirmed that the complex permittivity measured by the proposed method agrees very well with those measured by the conventional transmission-line method.Last, the interrelated measurements in this paper have been simulated with the HFSS software, then the measured results and the simulated results have been compared. By comparison, some useful and valuable conclusions have been achieved.