Research And Design Of Filter Power Divider Based On HMSIW

With the development of communication technology,the performance of its subsystem and components is improving continuously.With the increasing requirements for the plan circuits,high performance and integration of microwave systems,the integrated design of filter and power divider has become a hot topic.The design of filtering power divider effectively reduces the circuit size and insertion loss,improves noise performance and communication quality,under the premise of maintaining or even improving the original performance.Half-Mode Substrate Integrated Waveguide(HMSIW)provides similar transmission performance by reducing half volume of the Substrate Integrated Waveguide(SIW),while maintaining low loss,high quality factor,large power capacity,easy integration with planar circuits and other excellent performances.The stub-loaded HMSIW structure which works in the evanescent mode,can achieve miniaturization compared with the cavity structure in lowfrequency band,and can provide lower insertion loss compared with the microstrip structure.In this paper,the stub-loaded HMSIW structure is used to design of filtering power divider,the filtering equal power divider and unequal filtering power divider are developed.The main content can be summarized as follows:1.Filtering equal power divider design.Based on the equivalent model of the HMSIW evanescent mode,the filtering characteristics,design method and the method of applying the stub-loaded HMSIW structure to the filtering power divider design are studied.First,the fourthorder direct coupling structure is used to replace the quarter-wavelength converter,introducing a wideband high-selective filtering response.The method of loading resistors between symmetric resonators on the axial plane is discussed,which improves the isolation performance of the filtering power divider.The method of introducing transmission zeros in a low-order structure is studied.The third-order mixed-coupling structure that can introduce two transmission zeros is applied to the filter power divider design,which reduces the circuit size while achieving high selectivity.2.Unequal filtering power divider design.An equivalent alternative design method of filtering unequal power divider was studied.The high-low impedance transformation is realized by the open/short stub loaded microstrip structure.The quarter-wavelength transformer is replaced by the stub-loaded HMSIW structure.This structure introduces filtering response while achieving impedance transformation of the output port.Using the above design method,two unequal filter splitters were successfully designed.