Research Of3mm Passive Components Circuit Technology

Millimeter-wave frequency modulated continuous wave (FMCW) radars havemany significant features,but has not yet been widely used owing to the signal leakageproblem,RF(Radio Frequency) cancellation technology as one of the main ways to solvethe problem of signal leakage. Power coupling-dividing module and power combing-coupling module are two important passive modules in cancellation system which palyan important role in system power distribution and last combining the cancellationsignal and leakage signal.According to the indicators of the system,the two modulesconsist of6dB,10dB coupling couplers and3dB power divider(combiner).In thiscontext,we take a separate study on three millimeters passive power couplers andsplitters,and then select the appropriate circuit structure to synthesize the last modules.First of all,I research the Wilkinson power divider and the rate-race bridge andmicrostrip-waveguide transition of three millimeters circuit performance on the basis ofthe microstrip structure,then analyze the feasibility of microstrip circuit as thecomponent of module synthesis. Next,I analyzed the optimal processing method on thebasis of waveguide structure,according to this processing method,high frequencysimulation software HFSS was used to design and simulate a three-port waveguide E-plane T-section,a four-port rate-race rectangular waveguide bridge,a magic T and a3dBbranch waveguide directional coupler. The indicators is that the isolation of the isolatedports is less than-20dB,the insertion loss is-3dB,and the incident port return loss isless than-20dB.Through adjust the number and size of the branch in the branchwaveguide directional coupler can easily to get couplers of different coupling,sodesigned the branch waveguide coupler of6dB and10dB. Finally proposed two powercoupling-dividing module synthesis programs,including the form of6dB branchwaveguide coupler linked with magic T and the form of6dB branch waveguide couplerlinked with3dB branch waveguide coupler.Simulated and analyzed the two programsin the requirement of-20dB port-isolation and input port return loss and-9dB couplingport,choosing the most easy-to-processing scheme of6dB branch waveguide couplerwith3dB branch waveguide coupler as the final module.At the same time simulating the 3dB branch waveguide coupler linked with10dB branch waveguide coupler as the finalcombine-coupling module.The indicators also meet the requirements.At last using the engineering drawing software Solidworks and Autocad to drawmachine-processing drawings,test the module parts and compare simulation data withgiven test data,analyze the impact factors aimed at the differences and follow-up workwere prospected.