Measuring the microwave frequency relative permittivity of polyetherimide/ BaTi_4O_9 composites by using a rectangular cavity resonator

摘要

In this paper, high glass transition temperature (T_g) of polyetherimide (PEI) is used to mix with different weight percent (0-80 wt %) of BaTi_4O_9 (BT4) ceramic powder to form a flexible PEI/ BT4 composite. The relative permittivity of PEI/BT4 composites is developed from 1 to 16 GHz using the "rectangular cavity resonator" method. The relative permittivity of PEI/BT4 composites is calculated by observing the frequencies of resonant cavity modes. From the results of dielectric properties, the relative permittivity of PEI/BT4 composites is almost unchanged as the measured frequency is changed. It conjectures that the polarization mode does not exist in BT4 ceramic powder.