Research On Key Technologies For MEMS Electronic Calibration Chip Design And Processing

In radio frequency systems,RF MEMS switches,as important components to control the on-off of radio frequency signals,have important application value in microwave communication,radio frequency identification and other fields because of their low insertion loss,high isolation,and good linearity.In this paper,a calibration chip based on RF MEMS switch is designed to solve the problem of low calibration efficiency and poor accuracy of the current discrete devices,and provide a technical means for convenient,automated and intelligent microwave test systems.The main research contents of this article include:1)Two electronic calibration chip based on RF MEMS switch were designed.In view of the application requirements of DC?30GHz vector network analyzer,this paper first designs the RF MEMS single-pole double-throw switch,which has a insertion loss of less than0.25 d B and an isolation degree of greater than 20 d B in the DC?30GHz range.Secondly,based on the RF MEMS switch,two-port and four-port electronic calibration devices based on RF MEMS switches are proposed,and the electronic calibration functions of different port numbers are realized by optimizing the device structure.Among them,the two-port electronic calibration device works in the dc?26.5GHz range,the insertion loss is less than 0.5d B during pass-through calibration,the return loss is greater than-0.5d B at open and short circuit,and the return loss at load is less than-15 d B;the four-port electronic calibration device is working in the frequency band dc?12GHz,the insertion loss is less than 0.5d B during pass-through calibration,the return loss is greater than-0.5d B when opening and shorting,and the return loss at load is less than-12 d B.2)RF MEMS switch and two-port electronic calibration part based on RF MEMS switch were prepared by microsurface machining process technology.The rationality of its device design and the feasibility of the process design scheme are verified.Special research was conducted on the key processes in the processing of the device,such as the preparation of dielectric film,etching,thick glue lithography and other technologies,and the preparation process of the device was optimized,and the on-chip integrated calibration chip was prepared.3)The RF test system was built,and the mechanical properties and RF performance tests of the prepared devices were carried out.The test results show that the insertion loss in the pass-through state is less than 1.0d B,the port isolation is greater than 20 d B,and the average load resistance is 50?.Compared with the simulation results,the insertion loss is greater than the simulated value of 0.5d B,which is due to the dielectric loss caused by impurities such as water vapor present in the test environment,which does not affect the performance of the device and belongs to the controllable error range.