High-power Microwave Simulation Mode Converter Design

The High Power Microwave technology is a now and frontier science which rose in the 1970s.Because of the continuing demands of higher power, higher energy and higher frequency microwave sources in military and scientific research, the young has developed rapidly and is receiving widespread attention. Gyro-devices are new important type of millimeter wave device with the characteristics of high peak power, high average power, high gain, high efficiency and suitability bandwidth and so on. Microwave transmission and mode transformers are important part of gyrotron. The energy of gyrotron can be transmission and radiate with requisite methods.Based on the quasi-optical theory,this paper anaylsis of a TE03 mode 94GHz Vlasov mode converter and its working principle are described briefly. By using CST software to simulation and optimization, this paper presents a new method to design of Vlasov mode converter. The result show that The TE03 Vlasov mode converter including with single-reflector power conversion efficiency is about 87.36% in the center frequency 94GHz. By using of the EM simulator software, this paper calculate the power capacity of 3mm-band Vlasov mode converter for the first time. The result show that the power capacity is above 300MV and the phenomenon of breakdown theVlasov mode converter does not appear.Mode coupling with the bent of axis in a circular waveguide and gradual radius changes of the waveguide in overmoded waveguide is studied. On the base of coupling wave theory, the coupling wave equations and currently expression of coupling coefficient is educed. The circular waveguide mode conversion with waveguide radius tapered is discussed in detail. It also carries out the optimized analysis about the geometry structure of TE₀₃-TE₀₂-TE₀₁ mode converter. The TE₀₃-TE₀₂ power conversion efficiency is about 98.7% in the center frequency 94GHz.The conversion bandwidth is about 4.14% above efficiency 90%.In this way, The TE₀₂-TE₀₁ power conversion efficiency is about 98.4% in the center frequency 94GHz.The conversion bandwidth is about 7.83% above efficiency 90%.The optimal analysis of constant curvature circular waveguide mode converter is given.. By using of the EM simulator software, the results are contributed to design constant curvature circular waveguide mode converter with tight, the efficient and the wideband. It also carries out the optimized analysis about the geometry structure of TM₀₁-TE₁₁mode converter. The TM₀₁-TE₁₁ power conversion efficiency is about 98.6% in the center frequency 3.7GHz.The conversion bandwidth is about 19.1% above efficiency 90%.The converter design satisfies the high power transmission.