Realizing And Research Of An Automatic Setup For Scattering Parameter Of Microwave Based On MATLAB Platform

Microwave measurement is an important branch of microwave technology.Its development has close and inseparable relations with the application of microwave technology in various areas,and becomes a leader of the rapid development of microwave technology.As the rapid development of the large-scale integrated circuits,computer technology,signal processing technology and software technology, microwave measurement can be implemented by software technology today instead of original hardware technology.The new concept,such as "Software is the instrument","Network is the instrument" are bound to change the traditional test and measurement equipment design methodology,as a new microwave measurement trends.In many fields Of modern science and technology,the automatic measurement technology plays an increasingly important role.Automatic measurement means using additional equipment or devices(controller) to measure automatically in accordance with the law scheduled for the machinery,equipment or production facilities(measured objections).The objective of this study is to establish a soft real-time system between PC and various microwave measurement instruments by using General Purpose Interface Bus (GPIB) as a connector.MATLAB provides an environment called GUI,which is needed for creating a Virtual Instrument(Ⅵ).TheⅥcan then writes and read data from various microwave measurement instruments.The datasets are analyzed in MATLAB and the final result is displayed through the monitor.The communication between GPIB bus and PC is implemented by the Instrument Control Toolbox of MATLAB software,the Toolbox support GPIB bus-based communications, asynchronous communication and synchronous communication,and also event driven based communications.As the connection between GPIB bus and PC-specific implementation,we select the NI's GPIB-USB-HS controller.Finally,a variety of network corrections are set up approaching to eliminate the error due to microwave devices,connectors,transmission lines.After network correction,moving the values from reference plane to real device under test plane, then we can get the values which are much close to the real values.When researching the correction networks in order to obtain the smallest error,we analyze the strongpoint and drawback of various correction network,and different effects of various aspects in order to minimize the error of various applications.Experimental results show that the microwave scattering parameters of the automated microwave measurement systems improve the efficiency of measurement, thereby reducing the burden of testing staff,and Calibration network through the network is set up to reduce the error.It is shown that the automatic measurement system has good pratical application and prospect.