Gyrotron-TWT Operating Characteristics

The gyrotron traveling-wave tube (gyro-TWT) is a new type of millimeter amplifier which employs the electron cyclotron maser instability as a basis for the electron-electromagnetic wave interaction. A C-band gyro-TWT, employing the fundarnental cyclotron resonance interaction with the circularly polarized TE/sub 11/ dominant waveguide mode, has been constructed and tested. Initial power measurements yielded an output power of 50 kW at 60-kV beam voltage with 16.6-percent efficiency and 6-percent bandwidth. These measurements were recorded with a flat magnetic field. Subsequent experimental testing yieIded, for a magnetic field increasing in magnitude towards the output portion of the tube, 128-kW and 65-kV beam voltage at 24-percent electronic efficiency. The maximum efficiency was 26 percent at 120.5-kW peak power, with an instantaneous bandwidth of 7.25 percent as measured in a high-beam power mode (65 kV, 7 A). In the low-beam power mode (40 kV, 4 A), the efficiency was 9.8 percent at 18.8-kW peak power at 9.3-percent instantaneous bandwidth. Additional experimental results of AM and PM modulation coefficients, spectral purity, phase Iinearity, and noise figure are presented.     

Coaxial Relativistic Backward Wave Oscillator and Coaxial Master Oscillator-Power Amplifier

A two and one half dimensional particle-in-cell code MAGIC has been used to investigate the nonlinear beam-wave interaction in a coaxial relativistic backward wave oscillator(RBWO) and optimize the dependence of the output power on electron beam nature parameter, slow wave structure geometry and magnetic guide field. The optimum conditions for the coaxial RBWO were obtained. The simulation results show: the coaxial RBWO can generate 3.2GW peak output power at 10.2GHz in the TM₀₂ made when an annular electron beam of 20KA is accelerated across a diode potential of 600KV and guided through a section of uniform coaxial corrugated waveguide by an axial magnetic field of 25KG, the peak efficiency is about 27% . A novel coaxial master oscillator–power amplifier was presented in this paper.     

High power efficient dye amplifier pumped by copper vapor lasers

An extensive study has been performed on a dye amplifier pumped by copper vapor lasers. The amplifier utilizes a transverse pumping configuration in which the dye flow, pump beam, and dye extraction beam are mutually orthogonal. The operating characteristics of the amplifier have been studied using four dye-solvent systems which span the wavelength range continuously from 560 to 690 nm. Optimum conversion efficiencies of 18-30 percent at output powers of 0.41-0.76 W have been measured from the four dyes at a 6 kHz pulse repetition rate. The efficiencies and output powers were limited only by the available copper laser pump power. Analytic expressions have been obtained for the amplifier power gain and efficiency using a rate equation treatment of the system dynamics. Excellent agreement is obtained between the predicted and measured amplifier gain characteristics for rhodamine 6G.     

10kW级固体板条激光放大器设计与实验研究

针对传导冷却和端面抽运的激光增益模块特点,设计了一台10kW级高功率全固态板条激光放大器实验装置。分析了激光注入功率密度和入射角度等参数对激光放大器提取效率的影响。实验测试了注入功率密度与激光增益模块光-光转换效率的关系,实验结果与理论分析基本吻合。激光放大器实验装置的种子源通过一级预放大器和两级主放大器放大后获得了高功率和高光束质量的激光输出,激光放大器输出功率达为11.3kW,光束质量7.56倍衍射极限,出光时间110s,光-光转换效率达30%。     

The electron cyclotron maser as a high-power traveling wave amplifier of millimeter waves

The electron cyclotron maser instability has been exploited as the basis for a new type of traveling wave amplifier which operates at unusually high-power levels at millimeter wavelengths. The first experimental model of this amplifier has been operated at 35 GHz and has demonstrated a stable gain of 17 dB and an output power of 10 kW (unsaturated). The gain was linear over a dynamic range > 30 dB. The absolute value of the gain and its dependence on current and magnetic field were in excellent agreement with theoretical calculations. Bandwidth and saturated power have yet to be measured directly, but no fundamental problems were observed which will prevent successful achievement of the design predictions (viz., bandwidth ≃ 10 percent, power on the order of 10⁵W, efficiency > 10 percent).     

激光二极管抽运的主振荡级与功率放大器结构Nd∶YVO4激光器

为了实现固体激光器高功率、高光束质量的输出,设计了一种激光二极管(LD)阵列抽运的主振荡级与功率放大器(MOPA)结构的Nd∶YVO4激光器。该激光器的振荡级采用平-平谐振腔结构,并使用棱镜组对激光二极管阵列的抽运光整形,消除了激光二极管阵列抽运光不对称对振荡器输出光束质量的影响,在连续工作条件下获得了6.1 W的激光输出,其光束质量M2因子为M2x=1.14,M2y=1.13,光-光转换效率为25.6%。放大级采用具有近共焦、非稳腔特点的折叠光路结构,使振荡级激光光束10次通过放大级晶体,并且有效地抑制了放大自发辐射(ASE)和寄生振荡。在振荡级以6.1 W注入放大器时,得到最大输出功率26.8 W,此时放大器提取效率为29.1%,输出光束质量M2因子为M2x=2.08,M2y=1.92。     

输出功率50 W的脉冲染料激光放大器

推导了准稳态下横向抽运的脉冲染料激光放大器的简化速率方程,提出了双侧横向抽运方式的脉冲染料激光放大器的设计原则和设计方法.应用高功率脉冲染料激光放大器的物理设计结果,研制了输出功率为50 W的脉冲染料激光放大器的实验装置.采用铜蒸气激光(CVL)作为抽运光,在此染料激光放大器上进行了实验研究,获得染料激光输出功率为52 W,抽运激光功率提取效率为41%.给出了染料激光波长、注入染料激光功率以及抽运激光的时间和空间匹配特性与染料激光放大器输出激光功率和抽运激光功率提取效率的相互关系,讨论了染料溶液浓度对双侧横向抽运方式的脉冲染料激光放大器的输出光束质量的影响.     

A 25-W 5-GHz GaAs FET Amplifier for a Microwave Landing System

A 25-W 29-dB gain 5-GHz GaAs FET amplifier has been developed which can be used for a transmitter in the Microwave Landing System. By using 10-W class practical internally matched GaAs FET's hermetically sealed in ceramic packages, the four-stage amplifier has been constructed simply. The amplifier provides 30-W power output with 18.5 percent power efficiency at 17-dBm power input level. It also exhibited an exceffent AM/PM conversion of approximately 1°/dB, compared to 6°/dB for TWT amplifiers.     

ArF准分子激光器的窄线宽可调谐运转及注入放大

在一台快放电泵浦的ＡｒＦ准分子激光振荡放大系统的振荡级上采用光栅、扩束镜、光阑等腔内元件，用组合输出镜获得了线宽小于０．１ｎｍ，调谐范围～１ｎｍ的激光输出。注入到非稳腔结构的放大级，注入后放大级效率提高了约５０％，获得了平均３０ｍＪ／脉冲的高光束质量的窄线宽可调谐激光，最大单脉冲能量＞５０ｍＪ，并进行了氧气的吸收光谱实验。     

Design considerations for the high-power multicavity klystron

A confined-flow large-signal formulation of the klystron interaction equations is presented and applied to the analysis of the multicavity klystron amplifier. The effects of cavity voltage, cavity phase, drift length, and beam parameters are studied. The two- and three-cavity amplifiers are studied in detail, and several numerical examples of four-cavity klystrons are also given. A significant second-harmonic component of velocity modulation is shown to improve the dc to RF conversion efficiency. Two methods of obtaining this modulation are discussed. The large-signal theory presented here has been used to design a five-cavity klystron which is 50 percent efficient and has a controllable power transfer curve. Theoretical and experimental power transfer curves are presented for several 1 1/4-MW klystrons; the calculated output power is between 4 and 10 percent greater than the experimental values.     

基于共面臂波导魔T的Ka频段功率合成放大器

无线通信技术高速发展,为实现高速数据传输,需要提高频谱带宽,因此,毫米波技术成为新一代无线通信的关键技术之一。同时,毫米波技术在成像、深空通信、电子对抗等方面都有着广泛的应用。然而,单个固态毫米波放大器的输出功率往往无法满足需求,功率合成技术成为实现高功率输出的必然方法。传统的毫米波功率合成放大器往往体积过大或带宽较窄, 文中提出了一种基于共面臂波导魔T的毫米波功率合成放大器,该放大器基于共面臂波导魔T、波导-微带双探针耦合结构和HMC906 功率放大器芯片,在Ka频段具有宽带、高合成效率和结构紧凑的特点。在27.5~32.5GHz范围内,功率合成放大器饱和输出功率大于8W,合成效率高于85%。与传统的基于分支耦合线的功率放大器相比,体积减小了40%以上。     

A theoretical analysis and experimental confirmation of the optimally loaded and overdriven RF power amplifier

Although the conventional Class B approach to RF amplifier design yields high output power and reasonable collector efficiency (78.5 percent at maximum output power), neither the power nor the efficiency are optimum, and both are dependent on RF drive level. This paper presents an analysis of appropriately selected collector voltage and current waveforms which determine the load impedance at the fundamental and harmonically related frequencies; these conditions define the ClassB "optimum efficiency" case with 100 percent collector efficiency and 1.27 times the conventional Class B value of output power. If the RF drive level is increased, and the collector voltage and current waveforms are appropriately selected so that the amplifier is overdriven, a different load impedance is determined; these conditions define the "optimum power" case with 1.46 times the conventional Class B value of output power and 88 percent collector efficiency. The "optimum power" case has the added advantage that the output power and collector efficiency are essentially constant over a predetermined range of drive level. Finally, the theory is verified by the construction and testing of a UHF power amplifier having a power output of 46 watts and an over-all dc to RF conversion efficiency of 65 percent with a 1 dB for 10.5- dB insensitivity of output power to RF drive.     

Ka波段基波回旋行波管放大器的模拟与设计

完成了Ka波段基次谐波TE01模回旋行波管的初步设计,通过PIC模拟计算获得了回旋行波管稳定工作的详细物理图像和参数依赖关系．模拟计算表明,在电子注电压为100kV,电子注电流为20A,工作磁场为1．27T时,放大器可以获得大于450kW的输出功率、50dB增益、大于22．5％的效率和约为5％的带宽．     

A nonreentrant crossed-field amplifier with cycloiding injected beam

Nonreentrant injected-beam crossed-field amplifiers usually employ a thin laminar beam positioned well above the sole electrode. In operation, the beam is gradually bunched by a phase-focusing action. This paper describes the analysis and demonstration of such an amplifier, with an important difference: the electrons of the beam have random cycloidal trajectories extending to the sole instead of following the usual linear paths, Rapid and effective bunching is accomplished by collecting antiphase electrons on the sole. Experimental results are presented to show that the approach is useful for high current beams. For example, an output power of 600 watts was obtained at 10 dB gain from an 800 mA beam. The advantages and disadvantages of the cycloidal motion are discussed. The results of computations are given to show the desirable characteristics attainable; for example, a design for an amplifier with a cycloiding beam requires only 35 percent of the interaction length of a laminar-beam type for the same computed power output, gain and efficiency at the same cathode voltage.     

国产双锥形光纤实现4kW单模激光输出

基于自主研制的双锥形掺镱双包层光纤,开展了全光纤高功率光纤激光放大实验。激光系统实现了中心波长为1080 nm、最高功率为4 kW的单模激光输出,其光光效率和斜率效率分别为82%和83%,质量因子(M²)为1.33,拉曼抑制比为44 dB。实验结果表明,双锥形光纤具有同时提高非线性效应和模式不稳定性效应阈值的优势,有利于进一步提升高光束质量光纤激光器的输出功率。     

一种高效率逆F类Doherty射频功率放大器

为了进一步提高射频功放的输出能力,基于GaN HEMT功率器件,采用平衡式结构设计了一款工作频率为3.3 GHz 3.6 GHz的高效率逆F类Doherty结构射频功放。参照功放管的寄生参数等效电路网络,为获得逆F类功放理想的开关特性,设计了具有寄生参数补偿作用的谐波控制网络来抑制功放输出端的二次、三次谐波,同时结合Doherty功放结构特点,使其在6 dB功率回退的情况下仍具有较高的输出效率。仿真后,可得到其在3.3 GHz^3.6 GHz工作频带内的输出功率在40.4 dBm^41.8 dBm内,PAE为66%~77%,最大DE达到82.6%,功率回退6 dB处,功放的DE仍在69%左右,增益平坦度约为±1.5 dB。     

An Experimental Gyro-TWT

Three experimental gyro traveling wave tubes (TWT'S) have been built and tested. All tubes used a fundamental cyclotron resonance interaction with the circularly polarized TE/sup 0/sub 11/ dominant waveguide mode. The tubes differed in the length of the single circuit section and in the amount of distributed loss used. The experiments were conducted at 5 GHz, with the object of producing a design that could be scaled to 94 GHz. Results on the third experiment include measurements of stable gain as high as 24 dB small signal and 18 dB saturated. A saturated power output of 120 kW at a total beam efficiency of 26 percent was measured with a 3-dB saturated power output bandwidth of 6 percent. The design features of the tubes and the experimental results are described fully.     

Fabrication and performance of GaAs p+n junction and Schottky barrier millimeter IMPATT's

A recently developed procedure, incorporating both preferential electrochemical etching for wafer thinning and electroplating for heat sink formation has been applied to the fabrication of Kaband (26.5-40 GHz) GaAs IMPATT's. Both epitaxially grown GaAs p⁺n junction and Cr Schottky barrier diodes have been fabricated. This procedure makes possible the batch fabrication of small area diodes (<2 times 10^{-5}cm²) over a large wafer area. The diodes have been operated both in the oscillator and stable-amplifier mode. Power, efficiency, and noise performance of the devices is reported. The p⁺n diodes, which could withstand junction temperature of over 300°C, gave the best power and efficiency. Powers as high as 680 mW with 12.4 percent efficiency at 34.8 GHz and an efficiency as high as 16 percent with 390 mW at 29.5 GHz have been achieved. The Cr Schottky diodes were unable to withstand junction temperatures in excess of 200°C and therefore produced less power despite the potentially better power handling capability. The highest power obtained from a Cr Schottky is 470 mW with 12.5 percent efficiency at 34 GHz. Comparable oscillator noise performance has been obtained with both types of diode. The best AM (DSB) double sideband NSR obtained is -135 dB in a 100 Hz window at 1.5 MHz from the carrier. An rms frequency deviation as low as 13 Hz in a 100 Hz window has been observed with a power output of 164 mW at 35.4 GHz by raising the external Q to 138. A lowest FM noise measure of 23 dB was achieved by reducing output power to 16 mW. The amplifier noise figure measured for both p⁺n and Cr Schottky diodes is 26 dB.     

A New Design of Doherty Amplifiers Using Defected Ground Structure

In this letter, a new Doherty power amplifier having the ideal harmonic termination condition that has been usually ignored is proposed. A defected ground structure (DGS) is adopted on the ground pattern of the output lambda/4 impedance inverter of the carrier amplifier and output offset transmission line of the peaking amplifier that are essential for proper load modulation operation of a conventional Doherty amplifier. As a result of the second and third harmonic termination, excellent improvement in power added efficiency (PAE), gain, maximum output power as well as linearity is obtained. The acquired improvements in gain, maximum output power (P_{1 dB}), PAE, and adjacent channel leakage ratio to wideband code division multiple access 2FA signal are 0.33 dB, 0.42 dB, 12.7%, and 5.1 dB, respectively. Moreover, physical length of microstrip line is shortened fairly by DGS, therefore the whole amplifier circuit size is considerably reduced     

多单元半导体激光器的高亮度光纤耦合输出

设计并研制了一种多单元半导体激光器的高亮度光纤耦合输出模块.激光器芯片采用分子束外延(MBE)方法生长的宽波导、双量子阱结构AlGaAs/GaAs激光器外延材料,激光器模块采用4只准直的单条形大功率半导体激光器,器件腔长为2 mm,发光区宽度为100μm,单条形器件的连续输出功率为5.0 W,每两只单条形器件的准直输出光束经过空间合束后再通过偏振合束,实现了多单元器件输出的高光束质量功率合成,采用简单的平凸透镜实现了合束光束与100μm芯径、数值孔径(NA)0.22石英光纤的高效耦合,耦合效率高达79%,输出功率达10.17 W,光纤端面功率密度达1.0×105W/cm2.