Investigation On A V-Band Overmoded Radial-Line High Power Microwave Oscillator

In the trend of developing high-power,high-frequency,compact high-power microwave?HPM?,the device is inevitably limited by low power capacity and mode competition as its size decreases.In order to solve this problem,we propose a novel V-band radial-line relativistic backward wave oscillator?RBWO?,which operates on high mode to increase power capacity and reduce mode competition effectively.Because of this,it has potential on achieving high-power,high frequency,compact HPM resources.This paper includes the following aspects:First,we deduce the dispersion equation of radial-line slow-wave structures?SWSs?using Bognitz function,and verify the correction of that equation by comparing the numerical calculation results and software simulations.The influence of structural parameters on dispersion characteristics is also worth doing research.After that,we study several important physical parameters such as quality factor,starting current and coupling impendence of different working modes to obtain the mechanism of mode selection and control.Combined with the results of theoretical research,we design a novel V-band radial-line RBWO with asymmetrical SWSs.When diode voltage and current are 524kV and 16.27 kA respectively,the device works on TM₀₂ mode,and its output power and working frequency are 1.5 GW and 60.56 GHz respectively.At the same time,we propose a novel method,which can select the working mode and frequency of device only by changing the length of drift tube.At last,we design a unilateral slow wave structure to cope with the problem of assembly errors,which can have negative effects on efficiency of device.When diode voltage and current are 237 kV and 4.25 kA respectively,the device works on TM₀₂mode,and its output power and working frequency are 300 MW and 60.56 GHz respectively.By rounding the slow wave structures,we can decrease the maximum surface field to 0.95 MV/cm.