Study On Measurement Of Microwave Properties Of Dielectric Materials

In recent years, with the development of microwave communication technology, dielectric materials have become the current focus of research in the field of electronic materials. Accordingly, test technology on the characterization of their dielectric property parameters such as dielectric constant, dissipation factor has also been paid increasing attention. For different types, different dimensions, different test methods are developed. Each category is subdivided into a number of different methods.Begin with the view of researching on dielectric material, several representative test methods which are commonly used in the current study of dielectric materials are summarized and compared. According to the actual need, parallel plate resonator method is selected. We have solved the eigen-equation and simplified the characteristic equation. Matlab graphical method is combined with the experimental data to gain a more accurate solution of the eignvalue. Then we get a method to solve the low level resonant mode called TE011 in the dielectric constant measurement and ensue the correct mode is discriminated. The traditional measurement of surface resistance is based on the theoretical model in which the parallel plates are infinite. Considering the parallel plates are always limited in an actual situation, the loss factors are analyzed and amended. The dissipation factor is also amended. Then we study the design of sample size. Through optimizing each parts of the parallel plate resonator method, the accuracy of the measurement system is enhanced and the performance of the method is also improved. Finally, the error analysis of the obtained data is studied.We use the method of combining VB and Matlab to prepare a set of test software that can achieve automatic control, data acquisition and data processing. Through testing the microwave properties of known samples, the feasibility and accuracy of the automatic measurement system designed on the base of the revised theory are verified. We have also tested a new type of dielectric materials whose microwave dielectric properties are unknown. The data obtained can provide some references for further study. Finally,the error analysis of the data obtained is studied.The results show that theoretical analysis of our study is reasonable, and measurement system design is correct. Most dielectric materials can be tested fast, reliably and automatically. The system is of strong practicality.