Research On Dual-frequency High Power Microwave Synthesis Technology

High-power microwave(HPM)refers to electromagnetic waves with a frequency of 0.1 to 300 GHz and an output power greater than one hundred megawatts.Since World War II,HPM technology has developed rapidly under the traction of military applications.With the continuous expansion of application fields and functions,HPM power levels are increasingly demanding.A single HPM source is constrained by physical mechanism and process conditions.Power synthesis is an important technical approach to solve the above problems and meet the development requirements of application systems.Non-coherent power synthesis using frequency characteristics is one of the core development directions of HPM synthesis technology,and domestic and foreign scholars have carried out a lot of research work.However,the current focus of such research is mostly the synthesis between two or more frequency points in the same frequency band.Few reports have been reported on the co-polarized incoherent HPM power synthesis,such as X-band and Kuband,spanning almost one frequency doubling.This paper studies the co-polarized HPM synthesis technology of X and Ku bands.Firstly,the research status of high power microwave synthesis technology at home and abroad is summarized,and the possible technical approaches of this kind of cross-band dual-frequency synthesis are analyzed in detail.In-depth research on the core device highpower capacity duplexer of synthesis technology,and proposed the preliminary design scheme of X-and Ku-band non-coherent composite links.The paper studies and overcomes the following specific problems1.By comparing the transmission characteristics of the circular waveguide and the coaxial waveguide,Point out the advantages of coaxial waveguides in mode isolation,The technical contradiction between power capacity and mode competition in the design of Over-mode filters is solved by using coaxial waveguide structure with specific internal and external radius ratio.2.By comparing the dispersion characteristics of TEM mode and higher order mode in coaxial waveguide,A method for tuning the high-order mode resonant frequency by changing the radius of the coaxial inner conductor and changing the high-order mode propagation constant to Solved the problem of parasitic passband suppression of overmode filter;3.Starting from the physical relationship between power capacity and Q value of filter cavity,A method for appropriately expanding the working bandwidth by reducing the Q value,increasing the coupling amount between the resonators to improving the power capacity of the filter;4.Utilizing the angular symmetric transmission characteristics of the over-mode radial waveguide,Realized the design of X and Ku band high efficiency synthesizer,Overcoming the high-order parasitic problems caused by the traditional branched waveguide composite structure?The final designed duplexer better realizes the common aperture synthesis of X and Ku band links.The return loss of the X-band input channel is greater than 19 dB at 8~8.5GHz,the insertion loss is less than 0.5dB,and the isolation of the Ku-band electromagnetic wave can be more than 39 dB,and the power capacity is greater than 1GW;The Ku-band input channel has a return loss greater than 20 dB at 14.9-15.3 GHz,an insertion loss of less than 0.5 dB,and an isolation of more than 55 dB for X-band electromagnetic waves and a power capacity greater than 0.5 GW.