| Microwave plays an import role in the communication and radar system. The material used in the microwave system will crucially decide its performance. With the development of the communication, the microwave devices are asked to become smaller. Besides changing the structure of these devices, we can also use the material with high dielectric constant to achieve this object. BaxSr1-x TiO3(BSTO) is a kind of ferroelectric material with high dielectric constant controlled by the dc voltage. BSTO can be widely used in electric-control phase shifter and miniaturization of the antennas. But with the traditional method, the dielectric constant measurement of high dielectric constant material is difficult. It is hard to get an accurate result. In this paper, a new method based on dielectric resonator is presented. Both relative dielectricconstant and tgδ can be measured accurately.This paper includes five chapters. In the first chapter, the ferroelectric material BSTO's properties and applications are introduced. Traditional methods' limit in measuring high dielectric constant material is also introduced. And it is hard to measure accurately for the traditional methods. The new method based on dielectric resonator (DR) is presented, and then the dielectric measurement can be translated to a DR problem. Both approximate method and analysis method in solving the DR problem are introduced in the second chapter. In the third chapter, the FEM is used tosolve the DR problem. The formulas of relative dielectric constant and tgS arededuced. The full measurement system is described in the fourth chapter. Error analysis shows that the new method is creditable. The shortcoming of the measure method is discussed in the last chapter. And with some improvements, the method can achieve a higher accurateness.
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