REMOTE VECTOR NETWORK ANALYZERS FOR MICROWAVE ENGINEERING LEARNING

The benefits of using remote instrumentation in e-learning are well known. Remote instruments offer more flexibility when preparing laboratory practices with high cost equipment which are usually located at the university facilities. Students can be provided with anywhere and anytime lab access. From the point of view of the university economic management, using laboratory equipment and instruments through the Internet allows a better use of resources: the number of students who can access to the instruments is increased and also the equipment available time per student. For these reasons, the use of resources is optimized and with a few high cost equipment a bigger student group can be attended.

This paper describes an application developed at the Department of Telecommunication Engineering of the University of Jaén based on Agilent’s Vector Network Analyzers (VNAs) E5062A and involves the creation of remote laboratory seasons through the Internet for the purpose of microwave engineering learning. University of Jaén offers a mandatory semester course called “Transmisión por Soporte Físico” as part of the Telecommunication Engineering Master program. This course is mainly focused on the analysis and design of high frequency circuits. The topics covered are transmission lines, waveguide components, impedance matching and characterization and design of microwave networks by means of scattering parameters. A typical application of a VNA is the measurement of scattering parameters. The proposed remote VNA allows students to characterize a DUT (Device Under Test) placed in lab, and the equipment is remotely controlled by the student via the Internet by means of a Web Browser.

The Microwave and Radiofrequency Laboratory at the University of Jaén includes 9 Agilent’s VNAs E5062A connected to the lab Local Area Network (LAN). Vector Network Analyzer E5062A enables measurement until 3 GHz and support the Standard Commands for Programmable Instruments (SCPI) over a LAN network using TCP/IP sockets. The developed application runs over a server based on a PC connected to the lab LAN network. The application has been implemented by JavaServer Pages (JSP) technology. Apache-Tomcat software with MySQL database has been installed in the server. This server is the only equipment that can be accessed from outside the laboratory. When a student is remotely logged, his web client is assigned to a VNA by the server. The server deals with the management of the hardware resources. A web client controls the associated VNA by means of requests sent to the server. After a request is received in the server, this PC sends the proper SCPI command to control the corresponding VNA. After executing the SCPI command in the VNA, a VNA’s screen capture is shown in the web client.

The way to access to the developed application may be done as: a) students who want to measure using an available VNA, if it exists; b) course administrator who can manage the users and the VNAs in the application. The application allows course administrator to obtain statistical data on the use of the application by the student users.