The research of the curve vibration in vector network analyzer

Vector network analyzer is a kind of microwave measurement equipment, which can measure S parameter of the microwave chip and system. Through some kinds of calibration steps, it can get a high precision of measurement result. In this paper the author introduces a phenomenon in the research and development process of vector network analyzer. There are several factors that influence the stability of vector network analyzer. In this paper, the author mainly describes the phenomenon that when set the analyzer at “single trig”, the curve does not scan stably, and the vibration is quite large. Vector network analyzer mainly has signal generation part and signal receiving part. The signal generation part mainly has signal synthesizing board, frequency doubling module. The receiving part mainly has directional coupling part, broad band fundamental wave mixing module, IF adjust board, digital signal processing module, embedded computer module. Through the research of the signal generation part and receiving part, the author finds the phenomenon is the problem of mixer module. The mixer chip in the module is influenced by both the power of local oscillator and temperature. Using a larger power magnitude, the phenomenon will lessen a lot. In this paper, the author describes the process of experiments and the theoretical analysis.