Study On Computer-aided Design And Tuning Of Microwave Filters

As an important frequency selection device, microwave filters are widely used in communication systems. In resent years, along with the rapid development of wireless communication, especially mobile communication, microwave filters usually have rigorous performance and complicated structures. At the present, the synthesis theory of microwave filters is being perfected. However, the design and tuning of complex filter were still restricting the large scale production. Consequently, there is an urgent need for the development of computer-aid design and tuning techniques in practice.This thesis is mainly devoted to the theory and application of computer aided design and tuning techniques for microwave filters. Firstly, an overview of four different computer-aided tuning techniques is introduced. Further more, this article presents an efficient and robust approach for the design and tuning of microwave filters using model-based parameter extraction. This approach can be applied to lossless or lossy filters with cross coupling. Four numerical examples are presented to demonstrate the efficiency of the proposed technique. Then, the space mapping algorithm with model-based parameter estimation is introduced to the accurate design of cross-coupled filters. The proposed approach was demonstrated through two examples. Finally, the computer-aided design and tuning software is developed base on the synthesis theory of microwave filter and diplexer, the diagnosis techniques and the parameter estimation approach. This software can guide the technologists during the design, simulation and tuning of microwave filters.