Radio Frequency Measurement Technology And Application Of Dielectric Properties Of Engineering Dielectric Materials

With the increasing use of higher frequency of electronic equipment,the reasearch on electronic devices,electronic circuits,and encapsulation materials is becoming more and more important,the demand of functional materials are also increasing.The main parameters describing the electromagnetic properties of the functional materials are complex permittivity,complex permeability,shielding effectiveness and reflectivity,they characterize the effect of the interaction between the electromagnetic field and the functional material.The complex permittivity is one of the important parameters of the electromagnetic parameters of the dielectric material,the development of measurement technology is vital for the reasearch of dielectric properties of materials.It is necessary to accurately understand the relative complex permittivity of the dielectric material in judging the effect of the dielectric material in electromagnetic field.To scientifically evaluate the dielectric properties of dielectric materials and acquire a higher accuracy of the relative complex permittivity of the dielectric material and set up a perfect low frequency to high frequency relative permittivity test method,following reasearch are maded:The system of the test fixture of parallel plate capacitor was improved,a new test fixture of parallel plate capacitor was designed.The structure and the test method are improved,specifically including the improvement of the system of electrode,three-electrode and two-electrode systems were designed to increase the upper limit of the test frequency;A linear slide structure was used in the carriage system to ensure that the electrode can move smoothly;A gain phase port adapter was designed for 100kHz to 30MHz measurements;The calibration compensation was designed for the two-electrode system calibration compensation;The test method was changed from contacted electrode to non-contact electrode,which will greatly improve test accuracy.The relative complex permittivity is obtained from the coaxial fixture based on the transmission reflection method in the frequency of 100MHz to 3GHz.The polytetrafluoroethylene(PTFE),alumina ceramics,quartz glass and other low-loss materials and PCB epoxy board,phenolic resin of high-loss medium were measured at low frequency and high frequency,and compared with the standard value.The test accuracy of the fixture is analyzed specifically for the sample.Finally,a perfect low frequency to high frequency relative permittivity test method was set up.