Ka波段滤波器加载三间隙耦合腔输出回路的仿真和测试

扩展相互作用速调管由多个重入式多间隙耦合腔构成,毫米波段高功率微波源的需求推动了Ka波段扩展互作用速调管的研制.本文采用基于微波网络理论的多间隙耦合腔输出回路间隙阻抗冷测方法,对Ka波段滤波器加载三间隙耦合腔输出回路进行冷参数测试,得到该回路的间隙阻抗频率特性曲线与群时延曲线.并将冷测结果与三维电磁场软件仿真结果进行对比,分析了两者产生异同点的原因.从阻抗频率特性的测量结果可观察到该输出回路的相对“冷”带宽达到4.3％,满足设计要求.     

三间隙耦合输出回路间隙阻抗频率特性的测量

从多端口微波网络等效的角度,讨论多间隙耦合输出回路间隙阻抗频率特性的测试问题,并以X波段三间隙耦合输出回路为例,分别从模拟测量和实际测量两个方面确定了其间隙耦合阻抗的频率特性,简化了测量过程,为三间隙耦合输出电路工程应用提供了有效的实验手段.     

三间隙三模重叠耦合腔输出结构特性分析

讨论了三间隙耦合腔输出结构中各模式的谐振频率特性,分析了耦合系数对模式重叠过程的影响。以X波段为例,模拟计算了输出结构的群时延特性,研究了输出结构工作的稳定性。结果表明,在带内波动约1.7 dB的条件下,采用三模重叠,可获得6.61%的瞬时带宽,具有良好的稳定性。     

速调管双耦合口输出回路间隙阻抗频率特性的计算

采用等效电路理论,建立了双耦合口输出腔间隙阻抗频率特性的冷测模拟计算方法。运用该方法,并借助CST-MWS三维电磁场计算软件,计算分析了某S波段单间隙双耦合口输出腔的间隙阻抗频率特性。结果显示,本方法与采用场分析法及散射曲线法得到的结果符合良好。     

S波段宽带速调管输出回路的研究

给出了一种S波段宽带速调管,采用双间隙重叠模耦合腔展宽输出回路带宽,从等效电路出发计算其阻抗-频率曲线,并给出了测试结果。将设计的输出回路运用于整管研制中。热测结果表明,在250 MHz范围内,输出功率大于800 kW,满足整机设计要求。     

带有三间隙耦合输出腔的X波段EIK注波互作用系统研究

扩展互作用速调管是通过使用分布作用谐振腔技术来扩展其瞬时工作带宽,可以在高工作频段,实现高功率、高效率、高增益、宽频带的一种紧凑型微波真空器件,在军事、科学和商业领域有着广阔的应用前景。本文以X波段为例,设计了三间隙耦合腔输出结构,对其群时延特性及间隙阻抗特性进行了分析计算,设计了扩展互作用速调管高频互作用电路,通过加载、参差调谐等方法使整个高频系统的输出达到稳定,并且具有较大的输出带宽。结果表明,在X波段,在工作频率为f_0GHz,输入功率为200 W时,3 dB瞬时带宽达到11.5%。     

双间隙谐振腔耦合缝调谐结构的分析与模拟

根据双间隙耦合腔等效电路和电磁场理论,设计了加载在谐振腔耦合缝上的调谐结构。建立了加载此调谐结构的谐振腔等效电路模型,通过理论分析得此结构能够对工作在π模式的双间隙耦合腔进行频率调谐,改变重叠模式耦合腔阻抗特性,同时减小对间隙场形的影响。软件模拟与理论分析结果一致,验证了该调谐结构的有效性,为多间隙耦合腔高频电路的研制和进一步展宽速调管输出带宽具有重要的参考意义。     

盘荷波导结构高频特性分析及其在高功率速调管中的应用

以周期边界法、谐振法以及微扰法分别对盘荷波导结构色散特性、耦合阻抗进行分析,研究了不同结构参数下盘荷波导结构高频特性的变化规律.设计了C波段π/2模速调管盘荷波导输出结构,对其注-波互作用开展了PIC粒子模拟.计算结果表明,相对于传统单间隙圆柱输出腔,盘荷波导输出结构可以在获得高效率的同时显著降低输出间隙场强.     

速调管圆柱同轴谐振腔高阶TM310模式输出回路

设计了工作于高阶横磁TM310模式圆柱同轴谐振腔.模拟计算了六个漂移管间隙中心轴向谐振电场极大值位置处的特性阻抗.对于谐振腔加载空矩形波导和加载电感膜片滤波器矩形波导两种速调管输出回路,由微波电路理论和高频电磁场软件分别模拟计算了漂移管间隙中心的平均间隙阻抗和输出带宽.两种情形间隙阻抗的最大值分别为48.757 kΩ和14.328 kΩ;间隙阻抗的3dB带宽分别约为1.1MHz和2.8 MHz.研究表明,单间隙圆柱同轴输出腔高阶横磁TM310模式结构适用于高频、窄带和高功率多注速调管输出回路.     

传输法模拟滤波器型输出回路的间隙阻抗频率特性

利用传输法把滤波器型输出回路等效为双端口微波网络问题,通过理论分析,数值模拟和冷测实验证明了S21平方后的曲线能定性反映滤波器型输出回路的间隙阻抗频率特性.从而在仿真设计阶段,可将S21设为优化目标,利用三维电磁仿真软件的参数优化功能实现精确设计滤波器结构,比相位法,场分析法更加快捷准确.传输法同样适用于矢量网络分析仪冷测滤波器的实验,可消除系统拆装及波导元件引起的误差,使测量更加方便准确.     

A programmable ultra-low noise X-band exciter

A programmable ultra-low noise X-band exciter has been developed using commercial off-the-shelf components. Its phase noise is more than 10 dB below the best available microwave synthesizers. It covers a 7% frequency band with 0.1-Hz resolution. The X-band output at +23 dBm is a combination of signals from an X-band sapphire-loaded cavity oscillator (SLCO), a low noise UHF frequency synthesizer, and special-purpose frequency translation and up-conversion circuitry.     

950 keV, 3.95 MeV and 6 MeV X-band linacs for nondestructive evaluation and medicine

We are developing compact X-band linac X-ray sources for nondestructive evaluation and medicine. First, we develop a portable X-ray system by a 950 keV 9.4 GHz X-band linac to realize on-site inspection. We use a low power (250 kW) magnetron as an RF source for compactness of the whole system. Since the RF power source is quite small and the stored energy in the structure is also small, we faced the problem of beam loading and current/RF-power oscillation. We are analyzing the problem by the circuit model. We plan to use this system for erosion inspection of metal pipes of petrochemical complex. By adopting a side-coupling cavity design to avoid the oscillation, we have developed 6 MeV X-band (9.3 GHz) linac for pinpoint dynamic tracking cancer therapy. Furthermore, we are manufacturing 3.95 MeV X-band (9.3 GHz) linac X-ray source with flexible waveguides for on-site bridge inspection. Updated results and situations are presented.     

Group delay equalised monolithic microwave integrated circuit amplifier for ultra-wideband based on right/left-handed transmission line design approach

A group delay equalised InGaP/GaAs HBT monolithic microwave integrated circuit (MMIC) amplifier with an active balun for ultra-wideband (UWB) application has been developed. The MMIC consists of a broadband amplifier with an active balun and a group delay equaliser. The group delay equaliser was designed based on a theory using a composite right/left-handed (CRLH) transmission line. Adding a right-handed (RH) transmission line to a CRLH transmission line in parallel, a convex group delay characteristic is realised. Since various UWB components have concave group delay characteristics, the group delay equaliser can compensate a concave group delay characteristic of the amplifier in an operation frequency band. In this paper, dispersion, group delay and impedance characteristics for the proposed CRLH/RH circuit have been theoretically analysed. Moreover, a minimised group delay equaliser circuit on an MMIC has been designed and fabricated based on the proposed CRLH/RH circuit. A fabricated group delay equalised InGaP/GaAs HBT MMIC amplifier with an active balun exhibited an improved group delay characteristic compared with the MMIC amplifier without the group delay equaliser. The standard deviations of group delays for a frequency variation in a gain band were decreased from 12.8 to 5.5 ps at S₂₁ and decreased from 10.3 to 7.3 ps at S₃₁.     

Oscillator-based interface for measurand-plus-temperature readoutfrom resistive bridge sensors

A signal conditioning circuit based on a relaxation oscillator is proposed for use with resistive bridge sensors. The circuit provides a rectangular-wave output whose frequency is related to the bridge unbalance, and duty-cycle is a function of the overall sensor bridge resistance, hence of the sensor operating temperature. In this way, two measurement values are simultaneously and independently carried on the same output signal. The circuit makes use of a constant current bridge excitation which enables the connection of remote sensors without accuracy degradation, and moreover, for silicon piezoresistive sensors, provides a first-order temperature compensation. A frequency-doubling output stage significantly reduces the nonlinearity due to switching delay times, at the parity of output center frequency and span. Experimental results are reported on the characterization of both the circuit alone and interfaced to a silicon pressure sensor     

An adaptive path selection method for delay testing

For verifying the correctness of a circuit, not only its logic function, but also its timing behavior must be considered. Although the path delay fault model can handle part of the weakness of the gate delay fault model, it also has inherent deficiencies. Since the number of paths in a logic circuit is tremendous, exhaustively testing each signal propagation path is prohibitive. To deal with the weakness of traditional delay test techniques, based on the path delay fault model, a new delay test approach including a new delay test output observation method and an adaptive path selection method is proposed in this work. The basic idea of the approach is to measure the signal transition time for each delay test, and more paths are selected for a second-stage test (if necessary) to ensure the timing behavior of the circuit under test. Experimental results obtained by computer simulation demonstrate that a more thorough test is really a need if many significantly late signal transitions are observed     

Frequency Stabilization of X-Band Sources for Use in Frequency Synthesis into the Infrared

An X-band source of excellent frequency stability is needed in infrared frequency multiplication of high order. Such a source has been used in frequency multiplication by a factor of 401 using a point-contact Josephson junction as a frequency multiplier and mixer. Noise data on three X-band systems are reported. Two of these systems use klystrons as the source of X-band power; the other uses a Gunn oscillator. Each of these three systems employs both cavity and injection stabilization. Injection stabilization, using a quartz-oscillator-driven multiplier chain, provides the second-to-second and minute-to-minute stability needed for the Josephson junction experiment. To our knowledge, this is the first published noise data where cavity and injection stabilization are simultaneously employed. The quality of the best system reported here is much better-both around 1 Hz from the carrier and around 50 kHz from the carrier?than the source used to multiply by a factor of 401 to 3.8 THz.     

一种高精度延期件的研究

基于某弹对延期件的延期时间要求的精度高,设计了一种高精度延期件。通过火帽选型、延期药剂的确定,以及优化设计延期体与连接体结构,在延期体壳体输出端实体部分挖出一个圆圈,将连接体大、小两端位置颠倒,并增大小端外径至36 mm,同时增大连接体内径为18 mm,从而增大了连接体空腔容积,使连接体与延期体组合后的消爆空间增大,延期药在燃烧过程中形成的预热空腔容积增大,为延期药燃烧提供较为一致的燃烧空间,使延期药燃烧产生的压力对燃速的影响更加均匀、稳定,增加延期药剂燃烧的稳定性,达到提高延期精度的要求。试验结果表明:该设计满足高精度延期时间（6.6±0.8）s的要求,可为今后的高精度延期件的优化设计提供参考。     

A Frequency-Lock Method for the Measurement of Q Factors of Reflection and Transmission Resonators

A new method for the measurement of Q factors of reflection (single-ended) and transmission (double-ended) resonators has been developed. The basis of the technique is the locking of an oscillator to some point away from the center of the resonator response curve. This is accomplished by the introduction of a phase offset into a conventional oscillator-resonator stabilization circuit so as to make the stabilizer sensitive to both the real and imaginary portions of the voltage transfer coefficient of the resonator. From a determination of the phase and frequency shifts, the Q factor may be evaluated. The frequency-lock method shows promise of having significant advantages in speed, convenience, and accuracy over previous techniques. The basic features of this approach were successfully demonstrated in a measurement of the Q factor of an X-band reflection cavity. A circuit for fully automatic Q determinations is proposed. In this mode of operation, the device should be insensitive to changes in the eigen-frequency of the resonator and should be capable of measuring very small changes in Q.