Research And Design On Composite Functional Microwave Device Based On Microstrip Slot Line Hybrid Structure

Due to the rapid development of wireless communication technology,miniaturized,multifunctional,and highly integrated microwave passive devices are of great significance to improve the overall performance of wireless communication systems,which makes a leap for highly integrated composite functional microwave passive devices.It has become one of the hotspots in contemporary society at home and abroad.The composite functional microwave device is an integrated design of several microwave passive devices,which can simplify the complexity of the wireless communication system and effectively reduce the volume of the system,such as research on passive three-port devices such as balun filters and power division filters.In order to meet the needs of development,continue to explore more possibilities of composite functional microwave components.This thesis takes balun,power splitter and filter as the main design units,and aims to ombine a variety of microwave devices and filters.At the same time,the microstrip-slotline transition structure is taken as an important structure throughout the design.On this basis,a variety of filters with multiple functions are proposed.The main research contents of this thesis are arranged as follows:First of all,this thesis makes a brief introduction about the domestic and foreign development and research on the composite function filters,and then introduces the three-port network analysis method,filter design principle,etc.,in order to lay a solid theoretical foundation for the continued composite function filter design.Secondly,the thesis proposes two design methods of balun filter.The first one is a balun filter composed of a microstrip-slotline transition structure and a T-type multimode microstrip resonator:The field analysis of the microstrip-slotline transition structure and the slotline itself is performed,and the two T-type multimode resonators are placed on both sides of the slot line.When the signal is output from the two output ports,the phase difference of the two output signals is 180°,and the passband of the filter is produced by the T type multimode resonators.When designing the second type of balun filter,this thesis uses a branch-loaded dual-mode slot line resonator,and takes the main slot line as the axis of symmetry,and then places two output ports of the filters on both sides of the main slot line.The equal amplitude and inverted signal is output at two balanced output ports,realizing the function of the balun filter.The design results show that the two kinds of balun filters exhibit good frequency selection characteristics and balun characteristics,and they are also highly integrated,simple in structure and easy to process.Lastly,the thesis gives two designs of power division filters.Both of these power division filters are based on the branched slot line resonator and Gysel power divider structure.The difference is that the first type of power division filter introduces a transmission zero through the branch-loaded slot line resonator,and the second type of power division filter is based on the original structure and adopts the reverse phase of the microstrip-slotline transition structure.The results show that the power division filter has good filtering performance,and at the same time has good power distribution characteristics and good isolation,which satisfies the design requirements of composite microwave devices.