Theoretical And Experimental Researches On Magnetically Insulated Transmission Line Oscillator With Mutimodes And Single Frequency

A novel magnetically insulated transmission line oscillator-MILO with mutimodes and single frequency is put forward for the first time in the dissertation after basic theory of MILO has been generally studied. MILO with mutimodes and single frequency is an HPM (high power microwave) device with cross-field and low resistance, which does not only have the advantage of dispensing with magnetic and small volume as the original MILO, but also generate microwave with single frequency during modes competition. This kind of HPM device is a new research direction for it can make the frequency of microwave stable to achieve the experiment purpose better and its far field directional diagram has the characteristic of mutimodes, which enlarge the 3dB width and radiation area. It has a great of academic value, so I put forward hypothesis of MILO with mutimodes and single frequency, create an L-band model and prove its feasibility from high frequency analysis, PIC (particle in cell) simulation and theoretical experiment. At the same time some research of other technology of MILO and two kinds of new MILO is carried out.This thesis focuses in the following areasFirstly, the investigation of the background of HPM technology and the present development of MILO are introduced and the principle and research methods of MILO are pointed out. Then, the academic value of MILO with mutimodes and single frequency is explained.Secondly, a novel MILO which can generate microwave with stable frequency during modes competition is put forward by adjusting the SWS (slow wave structure) with the theory of interaction between electron beam and microwave. An L-band MILO with mutimodes and single frequency which works at 1.22GHz is designed based on the selecting methods of parameters of MILO structure and its high frequency analysis and PIC simulation are carried out, which proves that this novel MILO’s feasibility of stable frequency during modes competition caused by self-excitation or dissymmetrical excitation.Thirdly, a preliminary experiment of this novel MILO is carried out based on the optimized structure in simulation. Experimental system is built based on the condition in existence in laboratory, which contains pulse power supply, MILO, vacuum system and measurement system. Calibration method is also introduced. The radiation power and direction diagram are calculated by measuring the power density at different angle in spaces with BJ-32 antenna. Afterwards the feasibility of this novel MILO is proofed experimentally.Fourthly, to satisfy the environment condition, the investigation of cathode’s strut is carried out with theory simulation and experiment and the relation between starting voltage and input voltage for a MILO has also been analyzed.Fifthly, two kinds of new MILO, bf-MILO with axial partition and Ku-band MILO, are put forward, one of which has two 2 pieces of SWS with different period and cavity depth and generates stable bi-frequency TEM mode microwave of 1.25GHz and 1.65GHz. This kind of bifrequency MILO is convenient to the modes converter designing compared to the azimuthal partition ones. The other kind of MILO is a Ku-band MILO working at 13GHz, which improve the MILO’s energy metric factor (pf2) obviously comparing the L-band ones.