Design Of Multi-Pass Band Filter Based On Stub-Loaded Resonator

With the development of communication technology,people have higher requirement for communication system.High capacity,small volume,low cost have became the main goal.In order to achieve these goals,many technical problems need to be solved,and the design of microwave devices is a big challenge.And in the microwave devices design,selecting the appropriate filter can improve the performance of the system.When selecting a filter,the multi-pass filter becomes inevitable in order to allow the system to work simultaneously in multiple modes without increasing the system volume.In the design of filter,resonator is an important component.And the harmonic tuned resonator has multiple advantages and can make filter's performance more superior,thus it is widely used in the design of the filter.Due to stub-load resonators have controllable harmonic characteristic,therefore,in this thesis,based on the design of it,put forward to two kinds of filter design ideas,and designed filters perform well.(1)A three-pass band filter with independent adjustable harmonics is designed.Through the analysis of the resonator and the layout's design,the two-pass band filter is obtained.On the basis of the two passband filter,cascade resonators,and introduce two ground holes.A filter with multiple coupled paths is formed.And the coupling paths respectively control the coupling intensity of each pass bands,and make each passband bandwidth controllable.This approach improves the flexibility of harmonic passband bandwidth adjustment,and solves the inseparability of the harmonic passband bandwidths.(2)A nested filter is designed.By wrapping the other resonator with one resonator,realize the nesting of the resonator stucture,and design a compact three-pass band.First of all,the resonators are designed into open loop structure.Because the open loop resonators have extra space wasted inside,under the idea of miniaturization,in order to make full use of the space,and not to increase the filter size at the same time,but improve the performance of the filter,on the basis of two-pass band filter,the three-pass band filter is realized by using the SIR resonator to replace the feeders.