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1.
Higher mode excitation is very serious in the relativistic klystron amplifier, especially for the high gain relativistic amplifier working at tens of kilo-amperes. The mechanism of higher mode excitation is explored in the PIC simulation and it is shown that insufficient separation of adjacent cavities is the main cause of higher mode excitation. So RF lossy material mounted on the drift tube wall is adopted to suppress higher mode excitation. A high gain S-band relativistic klystron amplifier is designed for the beam current of 13 kA and the voltage of 1 MV. PIC simulation shows that the output power is 3.2 GW when the input power is only 2.8 kW. 相似文献
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Middle cavities between the input and output cavity can be used to decrease the required input RF power for the relativistic klystron amplifier.Meanwhile higher modes,which affect the working mode,are also easy to excite in a device with more middle cavities.In order for the positive feedback process for higher modes to be excited,a special measure is taken to increase the threshold current for such modes.Higher modes' excitation will be avoided when the threshold current is significantly larger than the beam current.So a high-gain S-band relativistic klystron amplifier is designed for the beam of current 5 kA and beam voltage 600 kV.Particle in cell simulations show that the gain is 1.6×105 with the input RF power of 6.8 kW,and that the output RF power reaches 1.1 GW. 相似文献
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为了克服强流高增益速调管放大器中的自激振荡和适应低阻抗脉冲功率源发展的需要,利用高阻抗X波段五腔高增益速调管放大器进行了离轴八注八管高增益速调管功率合成技术研究,在频率为9.47 GHz、模拟输出功率为284 MW、增益为51.6 d B和效率为35.5%条件下,该器件整管微波输出稳定.在三维模型中,在离轴54 mm条件下该器件的微波输出特性稳定.基于实验室现有4.5 T(长1.1 m,室温孔径为150 mm)超导磁体,进行了八注八管高增益速调管的整管模拟,每个器件实现284 MW的微波输出.最后,为实现GW级功率输出,利用HFSS软件设计了用于离轴八注八管高增益速调管功率合成的八合一功率合成器,将该合成器同八注八管高增益速调管结合,模拟得到功率为1.84 GW、增益为50.7 d B、效率为28.8%的微波输出. 相似文献
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利用SUPERFISH软件设计了一种兼具大间隙速调管及三轴速调管优势的C波段大间隙三轴速调管,对所设计大间隙三轴速调管的束流传输及调制情况进行了2维粒子模拟研究。模拟结果表明,三轴速调管设计需要特别关注"模式泄露"问题以及谨慎选择内导体接地支撑杆的位置,以获得稳定传输的电子束。综合考虑上述两个条件,在440 kV的二极管电压下,5.0 GHz,200 MW的强注入功率可以获得11.8 kA的基频调制积分电流,束流调制深度88%,调制电流峰峰值大于40 kA,且调制电流具有良好的频率及相位稳定性。在此基础上,初步模拟得到了大于2.0 GW的平均微波功率,平均效率约33.8%。 相似文献
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高频段相对论速调管放大器(RKA)是近年来高功率微波领域的研究热点之一,其发展主要受限于模式竞争、相位抖动和效率偏低等问题。设计了一种径向线RKA,主要由输入腔、两组非均匀双间隙群聚腔和三间隙提取腔等四部分构成。通过比较单双间隙群聚腔与电子束互作用的耦合系数,说明了非均匀双间隙群聚腔具备对电子束较强的调制能力。前端加载TEM模式反射器的非均匀双间隙群聚腔的工作在TM01-π模式,Q值较大,有利于谐振腔之间的能量隔离。采用两组非均匀双间隙群聚腔级联的方式,在注入功率仅10 kW情况下,实现短漂移管长度下电子束深度群聚达110%。粒子模拟结果表明,该器件具有效率高的优点,在电子束电压400 kV,电流5 kA,磁场强度0.4 T条件下,得到功率825 MW,频率14.25 GHz,效率41%的微波输出。 相似文献
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Mode control in a high-gain relativistic klystron amplifier 总被引:1,自引:0,他引:1
Middle cavities between the input and output cavity can be used to decrease the required input RF power for the relativistic klystron amplifier. Meanwhile higher modes, which affect the working mode, are also easy to excite in a device with more middle cavities. In order for the positive feedback process for higher modes to be excited, a special measure is taken to increase the threshold current for such modes. Higher modes' excitation will be avoided when the threshold current is significantly larger than the beam current. So a high-gain S-band relativistic klystron amplifier is designed for the beam of current 5 kA and beam voltage 600 kV. Particle in cell simulations show that the gain is 1.6 × 10^5 with the input RF power of 6.8 kW, and that the output RF power reaches 1.1 GW. 相似文献
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介绍利用20 GW加速器二极管产生的电子束源,开展S波段相对论速调管振荡器(RKO)的理论设计、粒子模拟和实验研究的情况.该RKO采用3个紧密耦合的圆柱腔作为振荡腔,束流经过一段漂移管的群聚后采用三轴输出腔提取微波.该振荡器具有起振时间快、结构紧凑、束波转换效率较高等优点.采用无箔空心阴极和0.9 T的恒流源磁场引出的电压1 MV、束流13kA、脉宽40 ns的环形电子束驱动RKO,单次运行输出了3.5 GW的辐射微波功率,效率27%,频率2.86 GHz,瞬时带宽2%;脉冲重复频率20 Hz运行时,输出
关键词:
相对论速调管
振荡器
三轴提取腔
高功率微波 相似文献
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采用MAGIC 2.5D模拟软件,建立了X波段11.424GHz相对论大功率速调管放大器的高频结构模型。该模型由5个简单药盒型谐振腔组成,包括1个输入腔、3个中间腔和1个输出腔。研究了该模型的高频特性,初步设计漂移管及各谐振腔结构参数,再结合热腔模拟,研究了输入腔的吸收匹配问题,依据各腔体对基波电流逐级调制情况,优化配合各腔体的间隙等结构参数,从而获得电子束的最佳调制状态,最后通过调节外加均匀磁场大小获得百MW功率输出,结果表明:在加速电压520kV、束电流460A、外加磁场0.4T的条件下,当注入信号功率为1kW时,基波电流调制深度达162%,最终输出功率105MW,效率43.5%,增益50dB。 相似文献
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A novel magnetically insulated transmission line oscillator (MILO) in which a modified HEM11 mode is taken as its main interaction mode (HEM11 mode MILO) is simulated and experimented in this paper. The excitation of the oscillation mode is made possible by carefully adjusting the arrangement of each resonant cavity in a two-dimensional slow wave structure. The special feature of such a device is that in the slow-wave-structure region, the interaction mode is HEM11 mode which is a TM-like one that could interact with electron beams effectively; and in the coaxial output region, the microwave mode is TE11 mode which has a favourable field density pattern to be directly radiated. Employing an electron beam of about 441 kV and 39.7 kA, the HEM11 mode MILO generates a high power microwave output of about 1.47 GW at 1.45 GHz in particle-in-cell simulation. The power conversion efficiency is about 8.4 % and the generated microwave is in a TEll-like circular polarization mode. In a preliminary experiment investigation, high power microwave is detected from the device with a frequency of 1.46 GHz, an output energy of 43 J 47 J, and a pulse duration of 44 ns-49 ns when the input voltage is 430 kV450 kV, and the diode current is 37 kA-39 kA. 相似文献
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带状注相对论扩展互作用速调管放大器是一种高功率、高频率的微波毫米波放大型器件, 具有广阔的应用前景. 本文分析了扩展互作用结构多间隙谐振腔的渡越时间效应, 推导了2π模场情况下谐振腔的能量交换系数和电子负载电导, 且通过计算表明工作在2π模式三间隙腔的电子负载电导是单间隙腔的9倍左右, 多间隙结构有利于提高器件效率. 利用三维粒子仿真软件, 对工作在Ka波段的带状注相对论扩展互作用速调管放大器进行了模拟研究, 采用宽高比为30:1的带状电子束以降低空间电荷效应, 在电子束电压为500 kV, 束流为1 kA, 轴向引导磁感应强度为0.8 T的情况下, 器件输出微波功率为190 MW, 频率为40 GHz, 器件效率为38%, 器件增益为69 dB. 相似文献
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Based on the hot electron effect in a semiconductor, an overmoded resistive sensor for 0.3-0.4 THz band is investi-gated. The distribution of electromagnetic field components, voltage standing wave ratio (VSWR), and the average electric field in the silicon block are obtained by using the three-dimensional finite-difference time-domain (FDTD) method. By adjusting several factors (such as the length, width, height and specific resistance of the silicon block) a novel sensor with optimal structural parameters that can be used as a power measurement device for high power terahertz pulse directly is proposed. The results show that the sensor has a relative sensitivity of about 0.24 kW 1, with a fluctuation of relative sensitivity of no more than ±22%, and the maximum of VSWR is 2.74 for 0.3-0.4 THz band. 相似文献
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YANG Jian-Hui LI Ping ZHANG Jian-Ping LI Hui-Li 《理论物理通讯》2008,50(8):468-472
Relativistic configuration interaction calculations for the states of 1s^22s^2, 1s^22s3l (l = s,p,d) and 1s^22p31 (l=s,p,d) configurations of iron are carried out using relativistic configuration interaction (RCI) and multi-configuration Dirac-Fock (MCDF) method in the active interaction approach. In the present calculation, a large-scale configuration expansion was used in describing the target states. These results are extensively compared with other available calculative and experimental and observed values, the corresponding present results are in good agreement with experimental and observed values, and some differences are found with other available calculative values. Because more relativistic effects are considered than before, the present results should be more accurate and reliable. 相似文献
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Multireference configuration interaction study on spectroscopic properties of low-lying electronic states of As2 molecule 下载免费PDF全文
The potential energy curves (PECs) of four electronic states (X1Σ+g , e3△u , a 3 Σ-u , and d 3Πg ) of an As 2 molecule are investigated employing the complete active space self-consistent field (CASSCF) method followed by the valence internally contracted multireference configuration interaction (MRCI) approach in conjunction with the correlation-consistent aug-cc-pV5Z basis set. The effect on PECs by the relativistic correction is taken into account. The way to consider the relativistic correction is to employ the second-order Douglas-Kroll Hamiltonian approximation. The correction is made at the level of a cc-pV5Z basis set. The PECs of the electronic states involved are extrapolated to the complete basis set limit. With the PECs, the spectroscopic parameters (Te , Re , ωe , ωexe , ωeye , αe , βe , γe , and Be ) of these electronic states are determined and compared in detail with those reported in the literature. Excellent agreement is found between the present results and the experimental data. The first 40 vibrational states are studied for each electronic state when the rotational quantum number J equals zero. In addition, the vibrational levels, inertial rotation and centrifugal distortion constants of d 3Πg electronic state are reported which are in excellent agreement with the available measurements. Comparison with the experimental data shows that the present results are both reliable and accurate. 相似文献
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In this paper, we present a high-efficiency S-band gallium nitride (GaN) power amplifier (PA). This amplifier is fabri- cated based on a self-developed GaN high-electron-mobility transistor (HEMT) with 10 mm gate width on SiC substrate. Harmonic manipulation circuits are presented in the amplifier. The matching networks consist of microstrip lines and discrete components. Open-circuited stub lines in both input and output are used to tune the 2rid harmonic wave and match the GaN HEMT to the highest efficiency condition. The developed amplifier delivers an output power of 48.5 dBm (70 W) with a power-added efficiency (PAE) of 72.2% at 2 GHz in pulse condition. When operating at 1.8-2.2 GHz (20% relative bandwidth), the amplifier provides an output power higher than 48 dBm (,-~ 65 W), with a PAE over 70% and a power gain above 15 dB. When operating in continuous-wave (CW) operating conditions, the amplifier gives an output power over 46 dBm (40 W) with PAE beyond 60% over the whole operation frequency range. 相似文献
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Relativistic mean-field theory and phase-shift analysis are combined together to investigate the elastic Coulomb scattering between electrons and unstable nuclei. Electron scattering at several different energies is studied and compared, in order to see the energy dependence of electron-nucleus scattering. It is shown that electron scattering at 200 MeV or 300 MeV can be used to reveal electron-nucleus scattering information around the first diffraction minimum. Shifts in opposite directions are obtained for the first diffraction minima of the electron scattering off the ground and first excited states of ^17F with ^16O as reference, and similar effects are obtained for ^18Ne. Besides, some neutron-rich N = 8 isotones are also studied. Results show that electron scattering will be very useful and important in studying both proton- and neutron-rich nuclei in the future. 相似文献