Research On Dual-band Microstrip Filter Based On SIR Theory

In the last few years, along with the more and more complicated electromagneticenvironment and more and more fine frequency spectrum division, selecting the appropriatefrequency and eliminating the noise has become a bottleneck that must be broken in the fieldof wireless communication. While to break this bottleneck, filter as an indispensable part hasan unprecedented boom and a great development.The main goal is to design a dual-band microstrip filter which can be applied to WLANRF system.The main work included an introduction to the development of the current filters,introduced the application of the principle of SIR microstrip structure, and design animproved hairpin microstrip SIR structure filter, as analysing the improved hairpin microstripSIR structure filter, designed a new four-level symmetry of the structure of the microstrip lineSIR dual-pass passband filter. Elaborated all aspects of the key technologies and design a newmodel, and at the same time did a large number of simulation experiments and analysis.This study mainly includes the following several aspects:This design is based on the theory of the structure of the microstrip SIR, first of alltalked about the basic design of the transmission characteristics of microstrip lines and radiofrequency (RF) filter, and then described the characteristics and applications of the microstripSIR structure.About designing the improved hairpin microstrip SIR filter, the author improved thetraditional structure of three-level SIR, removed one of the three SIR structures and the othertwo is still according to the traditional mode, the two sides of the third one coupled with theother two SIR structure’s the other two sides. In this way, the size of the filter is morecompact, and added another coupled way to broaden the second passband. Overall, theimproved design of the traditional three-SIR filter is smaller in size and better in the filtering,which makes it a better dual-pass passband filter.About designing a new microstrip filter based on the SIR theory, the author was inspiredby trying to improve the traditional hairpin filter, which is that the two sides of one SIRstructure can be used as two coupling parts. So the author brought forward a new structure,which is consist of two three-level SIR structure with two shared input SIR structure, and that makes a four-level SIR structure filter...