Microwave Measuring Line System Based On Virtual Instrument

Well known as microwave multimeter, microwave measuring line is a classical microwave measurement device. Although the new measurement instruments and methods are emerging continuously, microwave measuring line is still widely used in development of new band. In addition, for the clear principle and easy operation, microwave measuring line is irreplaceable by other modern experimental devices, as the role of helping studding microwave basic concept. Then the microwave measuring line experiment is always the indispensable part in the college microwave experiment courses.But the existing microwave measuring line experiments mostly adopt separate instruments, which results in heavy weight, big volume, bald ploy and week data processing ability. Applying pop virtual instrument technology, microwave measuring line experiment system based on virtual instrument concept is developed. According to the classical mathematical model of the microwave transmission line, and the analysis and simulation of the microstrip, measuring line with microstrip is designed. Meanwhile signal source is also designed and fixed. On the respect of data collecting, the displacement sense is implemented by photoelectric displacement sensor; and the voltage amplitude sense is implemented by the demodulation probe, DC amplifier and A/D converter. With the control of the MCU, data is collected and then send to PC through RS232. On the respect of data analysis, LabVIEW is chosen as the software development platform, which makes the measurement control and data processing automatic. The software is divided into four parts, main menu module, data collecting module, data analysis module and data simulation module. It not only can show the real-time standing wave on the microstrip and automatically analyze microwave parameters, but also can simulate the distributing of the standing wave on the microstip and save the data. The interface between the operator and the PC is friendly and is easy to control. So it can be considered as a practical and expansible multi-function testing analysis platform.