Research On Multi-frequency High Power Microwave Power Synthesis Technology

High-power microwave(HPM)refers to electromagnetic wave with maximum power higher than 100 MW and frequency between 1-300 GHz.As a kind of strong electromagnetic pulse,HPM is widely used in military and civil fields.As the core index of high-power microwave system,how to improve the output power of HPM system has attracted much attention and research.Limited by technology,technology and physics,the output power of a single HPM source is limited,while the HPM microwave power synthesis technology using multiple HPM sources to synthesize the output can effectively significantly improve the output power.HPM incoherent synthesis using frequency isolation is one of the important development directions in the field of HPM power synthesis in recent years.At present,the research on frequency isolated HPM incoherent synthesis is mostly dual-frequency power synthesis,while the research on multi-frequency power synthesis is less.Multifrequency power synthesis requires higher isolation between channels.Therefore,the key objective of this thesis is to solve the problem of insufficient power capacity and channel isolation of microwave components in the synthesis system,to achieve X-band multifrequency(three-frequency)microwave power synthesis.This thesis first compares various synthesis schemes,and decides to design the multi-frequency high power microwave frequency synthesis scheme by using the frequency isolation incoherent synthesis scheme.In order to avoid the impact of insufficient power capacity of the filter in the high frequency band,the input HPM signal is selected to first distribute power through a one-to-six channel power divider,then conduct frequency isolation and synthesis respectively,and finally output coupling through a six-in-one channel synthesizer.According to the synthesis scheme,the design of high-power microwave waveguide filter with high stopband width and power capacity up to 0.31 GW is completed through the selection of high-power filter,the selection of high mode isolation resonator,the analysis of filter coupling structure and topology.Then through the analysis of the types of common multiplexers,the coaxial waveguide multiplexer is selected to design the one-to-six channel power divider and combiner,and the mode conversion from the input circular waveguide TM01 mode to the coaxial waveguide TEM mode is realized through the transition structure.The transmission efficiency of the one-to-six channel power divider and combiner module is about 99.0%,and the power capacity is more than 3GW.Then,using the design method of terminal short pavement,the rectangular waveguide synthesizer for frequency isolation is designed.The average transmission efficiency of the synthesizer is about 99.1%,and the power capacity is more than 0.5GW.Through the design of the waveguide transmission structure,the overall design of the multi-frequency HPM power synthesis system has been completed.The whole combining system can achieve the power synthesis of three HPM channels with 1GW power and center frequencies of 8.6GHz,9.0GHz and 9.4GHz respectively,and the transmission efficiency is about 96.2%.Finally,based on the existing HPM experimental platform,a new circular waveguide six-petal deformable structure filter with a central frequency of 9.25 GHz is designed using the same structure as this thesis.The small-signal experiment of the filter verifies that the filter is in good agreement with the simulation results.The HPM power test results show that the power capacity of the filter exceeds 0.25 GW,which shows that the filter is feasible in the multi-frequency HPM power synthesis scheme in this thesis.