Study On The Theory And Application Of Microwave Substrate Parameters Automatic Test System

With the continuous development of the application of satellite positioning systems,the demand for satellite antennas composed of ceramic substrates has increased significantly.However,the inconsistency of substrate parameters is caused by the difference of process conditions in batch production.Deviation of the substrate parameters is too larger,which cause the performance of the antenna to decrease and further affect the production efficiency.Therefore,it is of great practical significance for improving the production efficiency of microwave substrates by studying the on-line suitable microwave substrate parameters measurement method and implementing the automatic sorting system of the substrate based on the measurement results.This paper focuses on two aspects to research.The first aspect is the theoretical study of microwave substrate testing.The second aspect is the construction of the microwave substrate automatic test and sorting system.The specific work is as follows:The first aspect,in the theory of microwave substrate testing,according to the working principle of the microstrip resonant ring,a folded microstrip resonant ring with the resonant frequency of 1575MHz is designed.Subsequently,the equivalent circuit model of the covered and uncovered microstrip resonant ring is proposed,respectively.And the corresponding equivalent circuit parameters are obtained by comparison with the HFSS simulation model.Furthermore,a novel method for extracting the complex permittivity of the substrate by using the phase of the S21 parameter and the characteristic phase is proposed.Finally,the formula of the relationship between complex permittivity and the phase of the S21 parameter and characteristic phase is obtained by fitting through the combination of simulation fitting and actual measurement,which lays the theoretical foundation for the subsequent automatic test and sorting system implementation.The second aspect,the microwave substrate automatic test and sorting system consists of two parts.The one part is the automatic test and evaluation of the substrate parameters,and the other part is the automatic sorting of the substrate.First,the substrate to be measured from the conveyor belt with a robot arm is grabbed and placed on the test platform by rotating the robot arm automatically.Subsequently,the test software automatically reads the phase information on the vector network analyzer and calculates the complex permittivity of the substrate.Then,the automatic evaluation software judges whether the substrate parameters are within the acceptable range.Finally,the robot arm places the finished test substrate into the corresponding area,such as qualified area or failed area.Accordingly,the automatic testing of microwave substrate parameters and the automatic sorting of substrates are achieved.In this paper,the development of the automatic test of microwave substrate parameters and sorting software are completed.What's more,the verification platform for automatic test and sorting system of microwave substrate parameters is built.The research results show that the theoretical analysis proposed in this paper is valid.On this basis,the automatic testing of microwave substrate parameters and automatic sorting of substrates are realized.And it provides a reference for the engineering application of on-line measurement and automatic sorting of microwave substrates.