Research Of W Band Power Combining Technology Based On Ridge Gap Waveguide

With the research and application of electromagnetic wave,the centimeter-wave spectrum becomes crowded,so the millimeter wave is naturally paid more and more attention.The ‘heart' of a millimeter wave system is power sourse.Solid-state power amplifier is widely used as power source for many millimeter-wave systems because of small size,low cost and high stability.However,solid-state power amplifier cannot provide enough power due to the limitations of semiconductor process,heat dissipation and other factors in millimeter-wave middle and high band.The power combining technology which can combine the power of several solid-state power amplifier into one output is an effective way to solve this problem.This thesis focuses on the W band(75?110 GHz)power combining technology,introduces the classification of power combining technology and the advantages of using ridge gap waveguide to build power combining network compared with the traditional waveguide,uses microstrip line model to derive the formula of characteristic impedance,attenuation constant and power handling capability based on ridge gap waveguide main mode field distribution is similar to microstrip lines,and verifies the formula by simulation software.Then,because of the solid-state power amplifier should be connected by 50 Ohm microstrip line,the planar and vertical transition structure from ridge gap waveguide to 50 ohm microstrip line is designed.The simulation indicate that the reflection coefficient,transfer coefficient and relative bandwidth of planar and vertical transition structure is less than-25 d B in 83?100 GHz and-20 d B in 78?104 GHz,-0.05 d B and-3.12 d B,18.6% and 28.6%,respectively.The planar transition structure is chosen to perform tolerance analysis and fabricate.Next,the necessity of isolation is illustrated by the S parameters of 4 way back to back power divider.The 4 way high isolation power divider is designed based on magic T and slot antenna.The test result shows the reflection coefficient is less than-15 d B and the isolation is more than 15 d B in the full W band,which is in good agreement with simulation.The method to increase isolation is designed slot on the upper lid.No extra structure is added.