Measurement Of The Complex Permittivity Of Microwave Dielectric Disc

Glass trays and glass ceramics ones in micro-wave ovens occasionally crack into pieces in normal working time. These trys are made of dielectric materials, choosing dielectric materials of right permittivity can dodge the risk of cracking. Besides in the domain of applications of micro-wave power, dielectric materials are widely used in other aspects of electronic science, communication technology. To use every dielectric materials rightly, scientists and engineers demand methods that can measure permittivity of materials in special frequency band accurately and fast.This dissertation give the definition of permittivity and introduce the most popular methods of measuring permittivity first. And then, lay special stress on analysing method of measuring permittivity of low loss materials by using cylinder resonant cavity. Design several models based on cavity perturbation theory. Simulate these models independently to find optimal size, shape and position of samples by electromagnetism simulation software. At last, work resonant cavity of right size, build a measurement system based on cylinder cavity perturbation method. Measure samples of low loss materials with big size.This dissertation introduce a helpful idea of complex permittivity measurement of low loss materials with big size.