Research On Extraction Method Of Microwave Filter Coupling Matrix And Design Of Auxiliary Debugging Software

Microwave filters play an important role in wireless communication systems.In recent years,the computer-aided debugging technology of microwave filters has been widely concerned by experts and scholars.In order to shorten the filter design cycle,improve the work efficiency of technicians and reduce the cost of product production,the coupling parameters can be quickly extracted through the real-time response of the filter,which makes the design and debugging of microwave filters more efficient,and the large-scale mass production of filters will become easier.The main work of this paper is to study the extraction method of microwave filter coupling matrix,and develop the corresponding auxiliary debugging software.The main work contents are summarized as follows:(1)For microwave filters with different topologies,the coupling matrix transformation method based on similarity transformation and the coupling matrix optimization method based on eigenvalue are deeply analyzed.Compared with the similar transformation method,the coupling matrix optimization method based on eigenvalue can not only extract some commonly used coupling matrices in topological structures such as CT and CQ.Other topological coupling matrixes that are difficult to be extracted by the eigenvalue-based coupling matrixes optimization method can also be extracted.(2)Aiming at the limitations and insufficient accuracy of the traditional coupling matrix optimization method for the topology structure,a hybrid optimization method was proposed,and the optimization process was divided into two steps.First,the coupling matrix optimization method based on eigenvalues was used to optimize the horizontal coupling matrix of order N+2 into a coupling matrix corresponding to the actual topology structure.Then the coupling matrix is taken as a new initial matrix,and further optimized by using lsqnonlin function of MATLAB through another objective function,and the coupling matrix is finally used for the design and debugging of the auxiliary filter.Finally,the feasibility and effectiveness of the method are verified by an example.(3)Based on the optimization method based on least square method,the auxiliary debugging software of microwave filter is developed,including the connection between host computer and vector network analyzer and the design and implementation of software interface based on MATLAB.The debugging examples of electromagnetic simulation model and physical debugging are given.The practicability of the software in the design and debugging of filters is verified.The results show that the software can make the process of filter debugging fast and efficient.