Research Of Microwave Passive Elements Based On MSTL Structure

With the rapid development of wireless electronic communication technology,in order to meet more and more complicated system requirements,integration and chips have become the trend of the future development of electronic systems.At the same time,the highly integrated system also brings other problems: how to meet the high-performance requirements of different frequency bands under the premise of integration.Traditional transmission lines such as microstrip and waveguides are difficult to achieve high integration and multiple frequency bands at the same time.However,the operational characteristics of the mode-selective transmission line(MSTL)that transmit the quasi-TEM mode at low frequency and transmit the quasi-TE10 mode at high frequency can combine the advantages of the two transmission lines to meet the work requirements in a complex environment.MSTL technology has the advantages of low loss,low dispersion and ultra-wide bandwidth,and also has the characteristics of high integration,low cost,and ease of mass production,adapting to the development trend of microwave technology today,and having broad development prospects.This article focuses on microwave passive devices based on mode-selected transmission line structure.The specific research work and results are summarized as follows:1.The guided-wave properties of MSTL has been studied.Including the structure and working principle of the mode selection transmission line,design criteria and mode analysis as well as loss characteristics and experimental results.2.On the basis of MSTL,a half mode mode-selective transmission line(HMMSTL)with nearly half the size of MSTL is creatively proposed,and its transmission theory is analyzed and verified through simulation.At the same time,the design and result analysis of the transfer structure of the mode selection transmission line and the half mode mode selection transmission line with the microstrip plane circuit are also carried out.3.The power divider design based on MSTL and HMMSTL.Firstly,the basic theory and performance index of power divider are studied.Based on this,two 3d B power divider based on MSTL and HMMSTL which operating in 5G dual band(4.8-5.0GHz and 24.75-27.5GHz)were designed,the good simulation results show that the two power dividers meet the working requirements.In addition,in combination with two 3d B power divider based on MSTL and HMMSTL,two Y-junction four way power dividers which working in the 5G dual band are designed,and the power divider works well in the working frequency band.4.Research on coupler based on MSTL.Firstly,the coupler principle,microstrip and waveguide coupler are briefly introduced.Two couplers based on MSTL are designed according to the traditional coupling technology.The feasibility of the traditional coupling technology applied to the design of the MSTL coupler is studied by simulation results,parameter scanning and electric field distribution.Finally,the reason why the traditional coupling technology is not suitable for the mode selection transmission line coupler design is analyzed.