Research And Implementation Of Mixer Measurement Technology Based On Vector Network Analyzer

Mixer is an important frequency conversion device,which has been widely used in the communication system.And its parameters will have a certain influence on the performance index of the communication system.Therefore,it is significant to accurately characterize the mixer parameters.Vector network analyzer(VNA)is a basic instrument for measuring microwave devices,whose has a unique frequency sweep measurement method,can easily measure the frequency response of the device.The traditional vector network analyzer can only measure the excitation response signal of the same frequency,and cannot measure the frequency conversion devices such as mixers.With the development of modern vector network analyzers,vector network analyzers capable of integrated phase-coherent receivers and frequency offset mode measurement have begun to appear,and it is possible to use vector network analyzers to measure the characteristics of mixers with high precision.This thesis will focus on the mixer measurement method based on the vector network analyzer,as well as the error model and error correction method in the measurement process.In the thesis,an algorithm for measuring the characteristic parameters of the mixer is studied.The algorithm can correct the measurement results of the mixer from the two aspects of amplitude and phase,and improve the algorithm through simulation and experimental verification,and finally complete the algorithm module with corresponding function.The specific work of the thesis is as follows:1.According to the measurement characteristics of the mixer,the linear error model of the vector network analyzer is refined.The mixer data correction is mainly completed from amplitude and phase.In terms of amplitude,the power meter is used for receiver error calibration;in terms of phase,the characteristics of the phase-coherent receiver and the comb wave generator are used for correction.On this basis,the algorithm for modifying the mixer parameters is deduced,and the algorithm is verified by ADS software simulation.2.A measurement platform is built to conduct experiments in view of the problems that may be encountered in the practical application of the algorithm,such as the influence of different calibration components and different error models on the measurement results,the influence of cross-frequency phase hopping,and the calibration data selection of the comb wave generator.According to the experimental results,the thesis formulates the corresponding algorithm modification scheme,and proposes an appropriate mixer measurement parameter setting scheme under the condition of ensuring high measurement accuracy and fast measurement speed.3.A measurement function extension module based on vector network analyzer hardware is designed using Lab Windows CVI,the workflow and program interface design are completed,and specific experiments are designed to verify the effectiveness of the module.The experimental results show that the parameters such as reflection,transmission and group delay of the mixer can be accurately obtained by using the algorithm.