Ka波段二次谐波回旋速调管放大器的PIC模拟

该文根据谐波回旋速调管放大器的注.波互作用特点,分析了放大器稳定工作的条件:对Ka波段二次谐波三腔回旋速调管放大器的注-波互作用进行了模拟计算,对放大器的注.波互作用电路参数进行了优化设计。模拟计算结果表明,在电子注电压为70kV,电子注电流15A,工作磁场为0.685T时,在35GHz频率放大器可以获得超过250kW的输出功率,大于21dB的增益,23%的效率和约为120MHz的带宽。计算结果为实际工程设计提供了有益的参考。     

Nonlinear analysis of a multi-cavity gyro-twystron

To preserve high gain, high efficiency and high power merits of gyroklystron, a gyro-twystron is designed using an electron beam with α(v_⊥/v_z) greater than unity. With a multi-cavity section of high gain, the length of the waveguide output section can be made shorter than the threshold length of the absolute instability without losing total system gain. Numerical simulations are carried out to analyze a ka-band gyro- twystron consisting of three TE₁₁₁ mode cavities and an output section of a TE₁₁ mode waveguide. Stability study is performed to ensure the tube without self-excited oscillations. With α=1.5, the 3-dB linear and saturated gain bandwidth in excess of 2 % can be obtained by stagger tuning for an 80 kV, 3 A electron beam with 5 % axial velocity spread. The maximum saturated gain is more than 55 dB at 33 % efficiency. By tapering the magnetic field of the last 2 cm of the interaction region, the efficiency can be increased to 43 % without degrading the bandwidth, which corresponds to an output power of 103 kW.     

Analysis of a low magnetic field TE m11 gyroklystron amplifier†

Large- and small-signal numerical calculations are presented for a two-cavity, low magnetic field gyroklystron amplifier operating in the TE _m11 whispering-gallery mode. The gyroklystron system modelled consists of a bunching cavity and an output cavity separated by a drift tube. For operation of both cavities at TE₅₁₁, gain and emission efficiency are studied for a high energy (γ = 1·6), low axial velocity (β_Verbar; = 0·1) electron beam. Prebunching prior to the output cavity in the gyroklystron leads to an increase of the maximum efficiency by more than a factor of two over that obtained from operating the output cavity as an oscillator. Model calculations are presented which show that magnetic field tapering greatly reduces the effects of any initial axial velocity spread in the electron beam, allowing high gain (?40 dB) and high efficiency (25-30%) to be achieved.     

8mm二次谐波回旋速调放大器的研究

对8mm高功率二次谐波回旋速调放大器进行了理论研究和优化设计,已研制出回旋速调放大器实验样管,并进行了热测实验,得到了如下结果:在中心频率为35GHz的情况下,得到的最大脉冲输出功率为180kW,效率为13%,增益为21dB;在电子束电压为58kV,电子束电流为25A的情况下,得到了150kW的输出功率,3dB带宽110MHz(0.3%).     

W波段四腔回旋速调管放大器

介绍了W波段四腔回旋速调管放大器的设计.放大器工作在基膜TE01圆电模式,电子束工作电压70 kV,工作电流6A,设计的双阳极磁控式注入电子枪,电子束纵横速度比1.5,速度零散小于4％.采用粒子模拟方法分析了各种参数对器件性能的影响.模拟结果显示,设计的放大器在电子束速度零散4％的情况下,增益35 dB,带宽800 MHz,输出功率100 kW,效率为23.8％.     

A High-Gain, 28GHz, 200kW Gyroklystron Amplifier

A design study of a high efficiency/gain gyroklystron amplifier is performed to demonstrate amplified radiation power of 200kW operating at 28GHz. A key design feature of the present gyroklystron amplifier is that the amplifier is designed to be high gain so that it can be saturated by a low power solid state power amplifier. A non-linear, time-dependent, large signal numerical code is used to predict tube performance. Simulations predict that a stable amplifier radiation power of 214kW is produced with a saturated gain of 54dB, an electronic efficiency of 37%, and a frequency bandwidth of 0.3% from a five-cavity gyroklystron amplifier. The amplifier gain is found to be very sensitive to a beam velocity spread.     

CMOS prototype image sensor with edge enhancement to compensate for blurring

Small signal analytical analysis and large signal numerical calculations are presented for a gyroklystron in which a low order (TE₀₁₁) mode in the bunching cavity is coupled by the electron beam to a high order (TE₀₄₁) mode in the output cavity. A drift region separates the two cavities. We demonstrate that the probunching of the beam before entering the output cavity not only enhances the interaction efficiency of the TE₀₄₁ mode but also improves the mode stability by suppressing the TE₂₄₁ mode. The gyroklystron may be operated either as an oscillator or as an amplifier by a small variation of the applied magnetic field. The effect of the beam velocity spread on the efficiency is also investigated. It is found that the operation of the gyroklystron is more sensitive to beam velocity spread than that of a gyromonotron. Optimum conditions for a cold beam are not necessarily those for a wam beam.     

Experimental study of a multimegawatt pulsed gyroklystron

A pulsed gyroklystron with the TE_5,3 output mode is studied. A gain of 30 dB is obtained at a frequency 30 GHz, an output power of 15 MW, an efficiency of 40%, a pulse duration of 0.35 μs, and a gain bandwidth of 50 MHz.     

34GHzTE01模基波回旋速调管高频系统设计与实验

利用场匹配理论,建立了具有突变结构谐振腔的级联散射矩阵。通过数值计算,研究了具有突变结构谐振腔中各模式的反射相移随漂移段半径变化、工作模式的反射相移随腔体半径的变化、腔体中各模式的传播常数随腔体半径的变化、谐振腔的腔体长度和半径的关系,并完成了Ka波段TE01模回旋速调管的输入腔、群聚腔、输出腔的设计。同时给出了一支Ka波段TE01模四腔基波回旋速调管高频系统和整管的优化设计方案。PIC模拟表明：在中心频率34GHz,注电压70kV,注电流11A的情况下,获得了输出功率390kW,饱和增益42.9dB,电子效率50.6%,3dB输出带宽360MHz的结果。 通过样管的热测实验显示在34GHz,注电压70kV,注电流11A,获得了301kW的稳定输出脉冲峰值功率,41.8dB的增益,39.1%的效率,285MHz的3dB输出带宽。     

多注速调管电子光学系统的研究

本文比较系统地阐述了在多注速调管电子光学系统中开展的研究工作。给出了周期反转永磁聚焦系统的设计方法和设计考虑,讨论了控制极调制多注电子枪设计中遇到的特殊问题和解决方法,建立了计算电子光学系统的二维磁场和电子轨迹计算软件,并应用这些软件设计和研制了S波段200kW多注宽带速调管的电子光学系统。该管输出功率180kW,带宽7.6％,效率44.4％,增益大于45dB,电子注通过率89％,高频通过率69-83％。设计计算与实验结果有较好的一致性。     

Design and computer simulation of a gyrotwystron

We have designed a 4.5 GHz gyrotwystron consisting of an input cavity, a stagger tuned intermediate cavity and an output waveguide operating in the TE°₁₁, mode. Using a non-linear simulation code, we predict operation with a saturated gain of 22 dB, an efficiency of 22.5%, an output power of 60 kW and a bandwidth of ～2%. The efficiency and gain are similar to those achieved in a three-cavity gyroklystron operating at the same frequency, but the bandwidth is about an order of magnitude larger. Changing the profile of the B field optimizes efficiency and gain but decreases the bandwidth.     

Self-consistent field large signal analysis of the gyroklystron

A self-consistent field slow-time scale model and computer code for gyroklystron simulation and analysis has been developed and applied to a representative three-stage CW gyroklystron design. The RF magnetic field interaction and provision for velocity distribution in the electron beam have been included in the formulation. The results of the simulation reveal the presence of interesting non-linear hysteresis-like features in the drive curve and frequency response under certain experimental conditions. Significant degradation of the device gain and efficiency characteristics is observed to occur for velocity spreads above 8%.     

Linear analysis of the gyroklystron with gaussian field profile

The paper presents the prebunching characteristics and the linear response of the output cavity of a two-state gyroklystron, with prescribed gaussian field profile. The influence of the RF magnetic field in the bunching process and cavity beam loading is taken into account, and analytical expressions are derived for the RF injected beam current in the output cavity, the bunching parameter, the mutual admittance, and the small-signal gain. Numerical results for the small-signal gain and the phase shift, as well as their response to beam characteristics and DC magnetic field variations, are also presented, for a particular TE01/TE04, 6 GHz, gyroklystron amplifier.     

W 波段五腔回旋速调管放大器的设计

W 波段回旋速调管具有高增益和高输出功率的特点,在军用雷达方面有广泛的应用。本方利用电磁粒子模拟 软件CHIPIC 设计了一个W 波段五腔回旋速调管,优化了互作用电路的结构和工作参数,分析了电子注与场的换能 过程以及工作频率对输出效率和增益的影响。该管的工作模式为TE01 模,当工作电压为70kV、电流为6A、频率为 93.8GHz 时获得了167.3kW 的最大输出功率和39.8%的工作效率。当工作频率为93.65GHz 时取得了50dB 的增益和 400MHz 的带宽。该模拟结果对回旋速调管在雷达方面的应用提供了理论依据。     

8mm二次谐波回旋速调管放大器中电子注-波互作用的研究

应用粒子模拟软件对设计的二次谐波三腔回旋速调管放大器进行了数值模拟。分析讨论了二次谐波注-波互作用过程中电子群聚的物理图景和特点，并研究了电子注电流和归一化引导中心半径对电子注-波互作用效率的影响。模拟结果表明，本文设计的二次谐波三腔回旋速调管放大器在35GHz频率可获得约293kW的峰值输出功率和约28％的电子效率。     

Efficient Output Mode Converter for 30 GHz Gyroklystron at IAP

An output mode converter for Ka-band multi-MW gyroklystron in the Institute of Applied Physics (IAP) operating in the TE₅₃ mode is suggested. Two variants of the converter, aimed for different applications, are presented: the TE₅₃ to TE₀₁ mode converter with power output along the device axis and the TE₅₃ mode to Gaussian wavebeam quasi-optical converter with a visor. The suggested designs include the built-in electron beam collector. The converters were designed using a new synthesis algorithm, which implies iterative improvement of the waveguide wall shape in order to achieve high efficiency. The calculation results were proven by HFSS simulation and low-power tests of one version of the converter.     

X波段同轴腔多注速调管的研究

开展了具有同轴谐振腔互作用电路和双模工作杆控电子枪的X波段同轴腔双模多注速调管的研究工作.结合数值计算和冷测实验,对工作于TM₃₁₀高次模的同轴谐振腔模式分布和特性参数进行研究,获得了可满足多注速调管要求的谐振腔特性阻抗和良好的模式稳定性.采用具有双控制极的新型杆控多注电子枪及电子光学系统,可使多注速调管具有双模的新工作特性,通过数值模拟获得了优化的几何参数和具有良好层流性和波动性的空心多电子注.对采用6个电子注和5个谐振腔的X波段多注速调管进行了注波互作用大信号计算,结果表明当电子注电压为21.5kV,脉冲电流为14.4A时,可在30MHz频带范围内获得的100kW左右的脉冲输出功率,互作用效率大于30%,增益大于36dB.     

Design of high-efficiency wide-bandwidth coupled-cavitytraveling-wave tube phase velocity tapers with simulated annealingalgorithms

The output circuit section of a traveling-wave tube (TWT) routinely contains an RF phase velocity taper for the purpose of increasing RF output power and efficiency. By slowing the RF phase velocity in approximate synchronism with the decelerating electron beam bunches, the taper increases power transfer from the beam to the RF wave. Recently, the computational optimization technique of simulated annealing was shown to be very effective in the design of an RF phase velocity taper that significantly increased computed RF power and efficiency of a coupled-cavity TWT. In this paper, two new broadband simulated annealing algorithms are presented that optimize (1) minimum saturated efficiency over a frequency bandwidth and (2) simultaneous bandwidth and minimum efficiency over the frequency band with constant input power. The algorithms were incorporated into the NASA 2.5-dimensional (2.5-D) coupled-cavity TWT computer model and used to design optimal phase velocity tapers using a 59-64 GHz coupled-cavity TWT as a baseline model. Compared to the baseline taper design, the computational results of the first broadband algorithm showed an improvement of 73.9% in minimum saturated efficiency. The second broadband algorithm indicates an improvement of 272.7% in minimum RF efficiency with constant input power drive and an increase in simultaneous bandwidth of 0.5 GHz over that calculated for the baseline TWT     

Theoretical analysis of gyrotron amplifier with undulated waveguide

In this paper the interaction between a relativistic electron beam moving in a static magnetic field and a travelling electromagnetic wave is analysed by using the kinetic power theorem. The concept of the electron bunching function is introduced to illustrate the bunching process of beam electrons as a whole. By numerical calculation, the energy exchange process between gyrating electrons and the travelling wave field is obtained in detail. The results of the calculation show that the imaginary part of the axial wave number does not stay constant along the interaction length and that the gain characteristic is non-linear. Based on this analytic method, the maximum output power and efficiency of the gyrotron amplifier with a uniform waveguide are calculated and are found to depend critically on the value of the static magnetic field and the operating frequency. A new type of gyrotron amplifier is suggested here. In this device the gyrating electrons interact with the travelling wave in an undulated waveguide. Its instantaneous bandwidth is somewhat broadened and the optimum value of applied magnetic field is not too critical.