气体激光器圆柱形微波激励谐振腔的微扰理论分析及其应用

导出了工作于ＴＭ０１０模的圆柱形微波等离子体腔中等离子体与腔谐振频率关系的精确解析式和微扰近似公式，比较结果表明：在微波激励低气压气体激光器中微扰理论可相当精确地分析微波等离子体对腔的扰动效应。给出了消除等离子体与管壳的扰动引起的腔失谐的方法，从而在气体激光器中成功地形成了稳定与均匀的微波等离子体和稳定的激光输出。用微扰理论使此腔又具有测量等离子体电子密度和管壳微波介电常数的功能     

介质加载圆柱谐振腔中TM0模的RMM分析

对介质加载圆柱谐振腔进行严格分析是进行微波电路设计和微波介电测试的基础。根据平行板多层介质径向波导的本征模分析，采用径向模式匹配法获得了介质加载圆柱谐振腔中TM0模的本征方程，在此基础上开发了计算TM0模谐振频率的程序，对特定结构进行了计算，结果与参考文献一致。     

Resonance characteristics of a cavity-operated electrodelesshigh-pressure microwave discharge system

To characterize the resonance behavior of cavity-operated electrodeless high-pressure microwave discharge systems, a microwave circuit is developed that allows high-power network analysis during the operation of the discharge. The frequency-dependent complex impedance of the cavity including the plasma is obtained from a reflection measurement in the range 1.5 GHz-4.5 GHz. This method allows an observation of the actual resonance frequency and the actual vectorial mismatch so that a coupling efficiency >99% can always be achieved with proper adjustment of the operation frequency and coupling probe. Experimental results with a cylindrical TM₀₁₀ cavity and a coaxially situated discharge show a decrease of the resonance frequency with increasing power (increasing plasma temperature, electron density, and electrical conductivity) depending on the discharge geometry and the plasma composition. In accordance with a simple one-dimensional model, the Q factor passes through a minimum at medium power levels, where the cavity discharge system absorbs the microwave energy most effectively     

基于瞬态微波光电导测试仪的谐振腔传感器设计

利用微波谐振腔微扰原理建立了应用于测量半导 体和发光材料的谐振腔的传感器模型。采用HFSS 仿真软件对谐振腔参数和结构进行仿真。仿真结果表明,采用矩形孔时,微波谐振腔中具有 符合实验要求 的电场形式以及电场强度;实验结果也表明,样品在采用矩形耦合孔的谐振腔获得了较强的 信号。将不同 的样品放置于谐振腔中,并用纳秒激光脉冲照射,获得了较理想的动力学曲线,证明该谐振 腔的实用性, 为下一步测量样品的介电常数和电导率等物理参数等实验奠定了基础。     

高Q超导谐振腔的实验研究

针对频率标准用超导腔的设计,通过理论分析及CST仿真优化得到了一种高Q纯铌超导谐振腔的设计。所设计超导腔工作模式为TM010模,谐振频率为4.452GHz,Q值在液氦温度4.2K时达到3.4×107,在减压降温到2K左右时达到1.9×109,实验结果与设计结果一致,验证了设计的正确性和实验装置的可行性。     

Feeding RF Power from a Self-Excited, Pulsed Source into a High-Q Resonant Load (Correspondence)

A problem frequently arising in microwave electronics is the feeding of pulsed power from a self-excited source into a high-Q resonant load. A typical example is the one of feeding power from a pulsed magnetron into a high-Q microwave cavity such as that used in a linear accelerator. In the past, it has been customary to use a stabilizing load in a series tee system which results in approximately half the magnetron power being fed into the high-Q cavity.     

A simple method for accurate loss tangent measurement ofdielectrics using a microwave resonant cavity

A simple yet rigorous method has been developed to enable the loss tangent of dielectrics, having a known relative permittivity, to be accurately measured using a waveguide resonant cavity. The novel method eliminates the need for any physical measurement, either on the cavity or dielectric sample under test. The only electrical parameters that need to be measured are resonant frequencies and Q-factors of a reference cavity and those of the same cavity loaded with the dielectric sample. One of the advantages of the new technique is that dielectrics, of arbitrary shape, can be characterized at very high microwave frequencies. The new method has been verified through measurement over X-band     

A new type of waveguide ring cavity for resonator and filterapplications

A new type of rectangular waveguide ring cavity has been developed for applications to resonators, filters, and multiplexers. The circuits have advantages of high Q and high power handling capability. H-plane and E-plane waveguide ring cavities have been investigated thoroughly in single-mode and dual-mode operations. For single-mode operation, regular resonant modes, split resonant modes, and forced resonant modes were explained by resonant mode charts of E-field points. Mechanically tuned and electronically tuned resonators built by adjusting the resonant modes between regular resonant modes and forced resonant modes have been demonstrated. For dual-mode operation, a dual-mode filter using a single H-plane ring cavity has been built with a bandwidth of 0.77%, a stopband attenuation of more than 40 dB, and a sharp gain slope transition. Another dual-mode filter which was formed by cascading two E-plane ring cavities has also been fabricated with a bandwidth of 1.12%, a stopband attenuation of 70 dB, a mode purity of 2 GHz at the center frequency of 26.82 GHz, and a sharp gain slope transition     

膜电阻作为微波电路封装谐振模式抑制层

通常将微波电路置于金属封装之内.如果该封装波导谐振模恰好位于电路工作频率范围之内,电路与封装谐振模间的耦合将干扰电路的工作.在腔内放入覆有膜电阻的介质基片,可以有效地削弱封装谐振模,避免了放入吸波材料的传统方法给军用、宇航用毫米波电路带来的可靠性和机械加工难题.膜电阻的吸波性能取决于膜电阻方阻值和介质层厚度,使用数值方法计算得到应用该方法削弱后的最低阶封装谐振模的品质因数.     

Computer Simulation of a 5.7GHz, 110kW Transit-Time Oscillator

A high-power transit-time oscillator producing 110kW at 5.7GHz in the TM₀₁₀ cavity mode is described. The device comprises a temperature-limited diode electron gun operating at 40A in the range from 28kV to 35kV and an intermediate coaxial cavity from which the microwave power is extracted through a TEM coaxial guide. The diode serves also as a resonant cavity, where electromagnetic oscillations are grown from noise. The effect of the applied voltage on both the output microwave power and the instability saturation time has been investigated leading to an optimal diode voltage of 33kV.     

Generation of high-power broad-band microwave pulses by picosecondoptoelectronic technique

A single-picosecond GaAs photoconductive switch is used to pulse excite a microwave resonant cavity, thus generating a variety of RF (radiofrequency) waveforms with picosecond synchronization. The length of the transmission line that connects the photoconductive switch and the cavity and the strength of input/output cavity coupling elements provide for continuous variation of the frequency distribution of the generated RF power. The generation of greater than 7-kW broadband microwave bursts is demonstrated     

THz Coherent Vavilov-Cherenkov Radiation in a Special Three-Mirror Cavity

In the modern science and technology a compact and having enough output power terahertz radiation source working in room temperature have earned great attention. This paper is devoted to utilize electron bunches stimulate Vavilov-Cherenkov Radiation (VCR) in a special three-mirror quasi-optical cavity to generate coherent THz waves. This novel three-mirror quasi-optical resonant cavity has the coaxial field pattern which enables field establish in this cavity effectively. The analytical theory of the radiation exited by a train of electron bunches in the special kind of three-mirror cavity has been carried out and the coherent VCR has been achieved by the computer simulation. All those shows that this method can be used to establish useful THz radiation source by the normal electron gun and the commonly used microwave devices.     

X 波段三轴相对论速调管放大器的分析与设计

研究了三轴相对论速调管放大器（TRKA）的模式泄漏和自激振荡问题,对干扰模式的电场分布进行了分析,得 知干扰模式在谐振腔中为TM21 模,而在同轴漂移管中耦合为TE21 模。针对干扰模式的传输特点采用在同轴漂移管中加 载吸波材料的方式进行抑制,通过三维粒子仿真软件分析了吸波材料的电导率和几何参数对微波吸收的影响,根据仿真 分析结果,对同轴漂移管中加载吸波材料的TRKA 结构进行了三维模拟研究,结果表明吸波材料能够很好抑制TRKA 的 自激振荡,模拟仿真实现TRKA 输出微波功率1.1GW,效率37%,增益42dB。     

基于不同边界条件的SIW谐振腔导模场分析及应用

总结了完备的六种不同边界条件的基片集成波导(SIW)谐振腔结构体系.基于镜像原理和亥姆霍兹方程,给出而不同边界条件下SIW谐振腔的导模场的闭式解.分析了所有边界条件下的谐振腔的场分布,与全波仿真分析、传输线模型法和空腔模型理论给出的结果一致.给出了各种边界条件下SIW谐振腔的谐振频率计算公式.基于提出的传输线附加额外的两个边界条件与谐振腔等效的原理,分析了在SIW谐振腔内,TE模、TM模与TEM模的共存机理.阐述了不同边界条件下的SIW谐振腔的演变关系.最后设计了基于不同边界条件的SIW谐振腔结构的双模带通滤波器和均衡器,该滤波器的两个模式,TE100(TEM模式)和TE102独立可调.器件的实测结果与仿真结果一致,验证了理论分析的正确性,为微波器件的小型化设计提供了思路.     

串联谐振型激光器用开关电源的研制

介绍了采用功率ＩＧＢＴ模块研制成功的大功率串联谐振型激光器用开关电源的工作原理及ＩＧＢＴ的过压、过流保护方法,给出了访原主回路、驱动电路结构及电源系统的相关波形,该电源已成功地应用地双光路激光焊接机上,与传统激光电源比较,有明显优越性。     

Mode coupling in superconducting parallel plate resonator in acavity with outer conductive enclosure

We have carefully studied the mode coupling effect from analysis of the measured microwave scattering parameters of superconducting films using a parallel-plate-resonator technique. Due to its high resolution and simplicity, this technique has been widely employed to identify the quality of high-T_c superconducting films by measuring the resonance bandwidth, from which the microwave surface resistance is directly derived. To minimize the radiation loss, the resonator is usually housed in a conductive cavity. Using this method, we observe that a number of strong “cavity” modes due to the test enclosure fall around the lowest TM mode of the superconducting resonator and that a strong interaction between these two types of resonant modes occurs when their eigenfrequencies are close, causing a significant distortion or a strong antiresonance for the resonator mode. To describe this effect, a coupled harmonic-oscillator model is proposed. We suggest that the interaction arises from a phase interference or a linear coupling among the individual oscillators. Our model fits very well the observed Fano-type asymmetric or antiresonant features, and thus can be used to extract the intrinsic Q of the superconducting resonator     

微空心阴极放电试验用软开关电源的研究

微空心阴极放电（MHCD）是在普通空心阴极放电的基础上提出的一种高气压下亚毫米级微放电技术.将MHCD作为大体积辉光放电的外部电离源（即等离子体源）,可以解决高气压下大体积辉光放电不稳定的问题.在MHCD实验的基础上,研制出可对MHCD气体放电模式（连续/脉冲）和输出功率进行调控的开关电源.这种开关电源可以与单片机、微机等其他外部控制设备相连.该电源采用全桥软开关技术,串联谐振并联输出,4个MOSFET管为主控制元件,实现了高频工作,响应快速.脉冲模式工作时避免了开关管的硬开关,减小了高次谐波对电网干扰;无需镇流电阻也可实现气体稳定放电.     

一体化高功率微波组件内部的电磁兼容分析

分析了高增益、高功率微波组件内部射频干扰场的特点,给出了腔体内的场分布图,认为引起功率管损坏的主要原因是组件隔离腔的谐振导致脉冲功率管连续波工作造成的。结合相关工程设计给出了根据组件的工作频率,选择隔离腔体的尺寸,从而避开腔体的谐振频率,对大功率微波管起到保护的作用。同时指出了微波吸收材料最为有效的粘贴位置,这对减小组件内部的射频干扰和组件减重都是有利的。另外还就引起谐振的原因进行了分析,可作为工程设计参考。     

Q band microwave-biased photoconductive detector

A microwave-biased photoconductive detector operating in a cavity resonant at 36 GHz is described. The potential advantages of working at this high microwave frequency are outlined, and the microwave system is described. A photocurrent gain of 55 is reported, and measurements show that this value is degraded by about 25% at optical-modulation frequencies approaching 1 MHz.     

TM/sub 0n0/ - and TM/sub m10/ - Mode Oversized Cylindrical Cavity Power Combiners

TM/sub m10/ -mode power combining is treated in addition to conventional TM/sub 0n0/-mode combining in a multiple-device oversized cylindrical cavity having a window output structure. Mode analysis gives the condition for stable power-combining operation in the desired mode. By experiments both on TM/sub 0n0/ -mode combining (n = 2, 3, and 4) and on TM/sub m10/ -mode combining (m = 2 and 8), it is shown that almost perfect power combining in the TM/sub 210/ mode can be achieved as in the TM/sub 020/ mode and that the power combining efficiency decreases gradually with increasing n or m. A possible advantage of TM/sub m10/ -mode combining in an oversized cavity is suggested based on the experimental result that power combining in the TM/sub 810/ mode gives higher efficiency than in the TM/sub 040/ mode.