Pulse shortening hinders improvement of microwave output energy for high power microwave tubes. So far, it is also an unresolved problem in the field of high power microwave devices.In this paper, relativistic backwar...Pulse shortening hinders improvement of microwave output energy for high power microwave tubes. So far, it is also an unresolved problem in the field of high power microwave devices.In this paper, relativistic backward wave tube (RBWO) is treated as an example to study the pulse shortening phenomena. The influences of gas existing in the tube and explosive emission in inner surface of RBWO are all investigated by means of the particle-in-cell method. Through the simulation results, it can be predicted that the background gas in the tube is one but not the most important factor resulting in pulse shortening, in order to broaden the pulse width of gas-filled RBWO, the pressure of the filled gas must be controlled in a proper value. The explosive emission in the surface of slow wave structure due to intense electric field is one of the most important factors causing pulse shortening in high power microwave tube. Some methods to overcome this kind of explosive emission are also given.展开更多
基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件...基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500k V、电流6.2k A、引导磁场强度0.46T时,得到频率为9.40GHz、功率为900MW、脉宽为32ns的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。展开更多
Research progresses on Cherenkov and transit-time high-power microwave(HPM)sources in National University of Defense Technology(NUDT)of China are presented.The research issues are focused on the following aspects.The ...Research progresses on Cherenkov and transit-time high-power microwave(HPM)sources in National University of Defense Technology(NUDT)of China are presented.The research issues are focused on the following aspects.The pulse-shortening phenomenon in O-type Cerenkov HPM devices is suppressed.The compact coaxial relativistic backward-wave oscillators(RBWOs)at low bands are developed.The power efficiency in M-Type HPM tubes without guiding magnetic field increased.The power capacities and power efficiencies in the triaxial klystron amplifier(TKA)and relativistic transit-time oscillator(TTO)at higher frequencies increased.In experiments,some exciting results were obtained.The X-band source generated 2 GW microwave power with a pulse duration of 110 ns in 30 Hz repetition mode.Both L-and P-band compact RBWOs generated over 2 GW microwave power with a power efficiency of over 30%.There is approximately a 75% decline of the volume compared with that of conventional RBWO under the same power capacity conditions.A 1.755 GHz MILO produced 3.1 GW microwave power with power efficiency of 10.4%.A 9.37 GHz TKA produced the 240 MW microwave power with the gain of 34 dB.A 14.3 GHz TTO produced 1 GW microwave power with power efficiency of 20%.展开更多
基金Supported by Fok Ying Tung Education Foundation (No. 81007) and National Natural Science Foundation of China (No. 10276011)
文摘Pulse shortening hinders improvement of microwave output energy for high power microwave tubes. So far, it is also an unresolved problem in the field of high power microwave devices.In this paper, relativistic backward wave tube (RBWO) is treated as an example to study the pulse shortening phenomena. The influences of gas existing in the tube and explosive emission in inner surface of RBWO are all investigated by means of the particle-in-cell method. Through the simulation results, it can be predicted that the background gas in the tube is one but not the most important factor resulting in pulse shortening, in order to broaden the pulse width of gas-filled RBWO, the pressure of the filled gas must be controlled in a proper value. The explosive emission in the surface of slow wave structure due to intense electric field is one of the most important factors causing pulse shortening in high power microwave tube. Some methods to overcome this kind of explosive emission are also given.
文摘基于现有永磁磁体的参数,并结合高功率微波器件的优点,设计了一个X波段低磁场相对论返波管振荡器,当引导磁场强度为0.48T、二极管束压和束流分别为530 k V和7.0 k A时,通过粒子模拟软件得到频率9.42GHz、功率1.11GW的模拟微波输出,器件束波转换效率30%。在强流电子束加速器平台上进行实验研究,当二极管电压500k V、电流6.2k A、引导磁场强度0.46T时,得到频率为9.40GHz、功率为900MW、脉宽为32ns的微波输出。该实验结果为低磁场器件实现高功率、高效率微波输出及永磁包装打下了良好的基础。
基金supported by the National Natural Science Funds Fund of China under Grant No.11505288Provincial Natural Science Foundation of Hunanscientific effort project of NUDT.
文摘Research progresses on Cherenkov and transit-time high-power microwave(HPM)sources in National University of Defense Technology(NUDT)of China are presented.The research issues are focused on the following aspects.The pulse-shortening phenomenon in O-type Cerenkov HPM devices is suppressed.The compact coaxial relativistic backward-wave oscillators(RBWOs)at low bands are developed.The power efficiency in M-Type HPM tubes without guiding magnetic field increased.The power capacities and power efficiencies in the triaxial klystron amplifier(TKA)and relativistic transit-time oscillator(TTO)at higher frequencies increased.In experiments,some exciting results were obtained.The X-band source generated 2 GW microwave power with a pulse duration of 110 ns in 30 Hz repetition mode.Both L-and P-band compact RBWOs generated over 2 GW microwave power with a power efficiency of over 30%.There is approximately a 75% decline of the volume compared with that of conventional RBWO under the same power capacity conditions.A 1.755 GHz MILO produced 3.1 GW microwave power with power efficiency of 10.4%.A 9.37 GHz TKA produced the 240 MW microwave power with the gain of 34 dB.A 14.3 GHz TTO produced 1 GW microwave power with power efficiency of 20%.
