A Coaxial Bragg Reflector for Cyclotron Autoresonance Maser Oscillators

A coaxial Bragg reflector is suggested for the application in the cyclotron autoresonance masers (CARMs), where both the outer wall and inner rod are corrugated with weak axisymmetric-sinusoidal-ripple, and a concept design is presented. It is found that, compared to the cylindrical Bragg reflector, the coaxial Bragg reflector has larger dimensional size, narrower bandwidth, and larger eigenvalue intervals. These peculiarities are favorable to the mode selectivity, the ability of dissipating the ohmic heat on the wall, the oscillating startup of the operating mode, and machining manufacture, and therefore, this new kind of Bragg reflector can be developed into a coaxial resonator for the high-power CARMs     

Nonlinear Investigation of a Coaxial-Waveguide Cyclotron Autoresonance Maser Amplifier

A nonlinear approach is presented to simulate the coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier. Simulation shows an interesting result that the efficiency of a coaxial-waveguide CARM amplifier may be increased from 7.5% to 33.9% by tapering the magnetic field.     

Linear Study of a Large-orbit Coaxial-waveguide Cyclotron Autoresonance Maser Amplifier

A linear theory based on Maxwell-Vlasov equations and the Laplace transform is presented to describe the large-orbit coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier. A 35-GHz, TE_5,1-mode large-orbit coaxial-waveguide CARM amplifier is specifically analyzed. Good agreement between the linear theory and the nonlinear simulations is found in the exponentially growing region of the wave. Results show that the operating magnetic field and the electron-beam energy and average radius substantially affect the power, and especially, a small beam current may be unsuitable to a large-orbit CARM amplifier operation.     

有大回旋半径电子束环的回旋自共振微波激射器的特性研究

本文用线性化弗拉索夫-麦克斯韦方程分析了有大回旋半径电子束环的回旋自共振微波激射器的工作特性,并指出不可能工作在TE_on和TM_on模式,为此可采用部分填充介质的波导。     

Power Enhancement of a Small-Orbit Coaxial Cyclotron Autoresonance Maser (CARM) by Employing an External Radial Electrostatic Field

A proposal is presented to enhance the saturation power of a small-orbit coaxial cyclotron autoresonance maser (CARM) by employing an external electrostatic voltage. Nonlinear simulations show possible increase of 22% of the saturation power with high gain of 67 dB for a transverse electric mode at frequency of 140 GHz. Influences of initial parameters on the saturation power are simulated. It is found that due to the use of an external electrostatic field, saturation power of the wave is sensitive to the ratio of the transverse velocity to the axial velocity, as well as to the spread of the transverse velocity. The physical mechanism of the power enhancement may be that the radial force produced by the radial electrostatic field superposes an extra motion on the electron beam and thus causes an extra energy coupling between the electron beam and the radial electric component of the wave.     

Linear Analysis of a Cyclotron Autoresonance Maser (CARM) Operating in a Transverse Magnetic Mode

In the fast-wave devices like gyrotron, gyro-peniotron and cyclotron autoresonance maser (CARM) that generate millimeter and sub-millimeter waves, the transverse dimensions of the resonator and the output cylindrical waveguide become small. In order to prevent loss of electrons and thermal loading of the rf structure, the electron beam must be kept relatively far from the walls. The latter requirement demands smaller transverse dimensions of the helical electron beam as well. In this paper linear formulation of a CARM operating in a general transverse-magnetic (TM) mode is derived, and a detailed analysis of the influences of the parameters is presented for the TM_1,1 mode CARM. It is found that, compared to the TE_1,1 mode which is often employed in gyrotron traveling wave tube (gyro-TWT) and CARM experiments, the TM_1,1 mode has a greater eigen value and consequently leads to a greater waveguide radius for a given cutoff wave number, and also, allows the electron beam to be settled close to the waveguide axis to have a small transverse dimension. Results show that a TM-mode CARM can reach high power and ultrahigh gain, just as a TE-mode CARM or a TE-mode gyro-TWT does.     

Nonlinear Simulation of a Cyclotron Autoresonance Maser (CARM) Operating in a Transverse Magnetic Mode

In the gyrotron operation, the transverse-magnetic (TM) mode is excluded because the TM mode instability vanishes when the vacuum waveguide mode and the beam mode are at grazing incidence. However, situation changes in a cyclotron autoresonance maser (CARM) interaction. In this paper nonlinear formulation of a TM-mode CARM is derived, and detailed simulations are presented for the TM_1,1-mode CARM. Simulation results show that a TM_1,1-mode CARM can reach high power of megawatts and ultrahigh gain of more than 70 dB, as a TE_1,1-mode gyrotron traveling wave tube (gyro-TWT) and TE_1,1-mode CARM did in the reported experiments.     

单模光折变振荡器的输出及稳定特性（φ_0≠π／2）

在泵浦光非衰减的近似条件下给出了单模环形光折变振荡器中信号光随时间的演化方程，在此基础上得到了定态输出光强和频率牵引关系，并把非局域相位移动人作为可变参数，系统地分析了它对定态输出的影响。另外线性稳定性分析表明，单模光折变振荡器具有良好的稳定特性。     

毫米波均衡器同轴谐振腔内导体结构的设计与比较

摘要：对组成毫米波均衡器的核心部分，即主传输线、谐振腔的初步设计进行了介绍，并对谐振腔进行了初步分析与仿真。在仿真过程中发现了毫米波均衡器的一些新特点、新现象，并对其做了初步的探讨。在此基础上，重新设计了谐振腔内导体的结构，通过分析与仿真，基本消除了毫米波波段出现的一些不良影响，并可以对谐振频率、衰减幅度和品质因数进行调谐，基本具备了均衡器对谐振腔子结构的要求，这对今后毫米波均衡器的设计与深入研究有一定的帮助。     

频率可调太赫兹回旋振荡管互作用电路的设计与研究

根据动态核极化核磁共振成像技术对回旋振荡管的要求,设计了130 GHz 回旋振荡管的注波互作用电路,基于线性理论对互作用电路进行了研究并选择了合适的工作点,分析了电路的频率调节特性。利用相对论电子回旋脉塞非线性理论对互作用系统进行了模拟和计算,优化了工作参数,计算了磁场及电子注参数对输出功率及效率的影响。最后,用粒子模拟方法进行了模拟并与非线性理论结果进行了比较,两者符合得很好。模拟结果显示,当电压为10 kV、电流为0.3 A、磁场强度由2.34 T 增加到2.41 T 时,输出功率由1310 W 减小到230 W,对应的效率分别为43.6%和7.7%,振荡管的频率可调范围约为2.7 GHz。     

太赫兹扩展互作用振荡器输出结构的设计与分析

扩展互作用振荡器由于具有结构紧凑、工作电压低、效率高等特点成为真空电子学太赫兹辐射源的重要研究 方向,在高分辨成像雷达、保密通信等方面具有广泛的应用前景。扩展互作用振荡器输出段是该器件输出THz 的关 键部分,其输出特性对扩展互作用振荡器的整体性能有着至关重要的作用。本文采用仿真软件模拟计算的方法,对扩 展互作用振荡器输出段的S 参数进行了较为详细的研究,并且对中心轴对称直渐变过渡波导、平面对称直渐变过渡波 导和阶梯过渡波导式结构的输出结构进行了比较研究,本文的结果对后续EIO 的设计与研究具有一定的参考意义和指 导价值。     

Design of a 5.305 GHz Dielectric Resonator Oscillator with Simulation and Optimization

The design of a 5.305 GHz series feedback free running dielectric resonator oscillator （DRO） is presented. Its simulation and optimization are realized by obtaining the unloaded Q factor of the cavity dielectric resonator （DR） and analyzing the linear and nonlinear models of the DRO. CAD packages of DR_Rez and Agilent Advance Design System （ADS） are used and the best tradeoff among the output power, phase noise, and frequency stability is achieved. With the result of simulation, a physical oscillator prototype is constructed. The measured results show the good agreement with those of simulation.     

Application of a Microwave Coaxial Bragg Structure for the Measurement of Parameters of Insulators

Journal of Communications Technology and Electronics - A method for the measurement of the complex permittivity of insulators using a microwave coaxial photonic crystal is proposed and implemented....     

60GHz缺陷态同轴布喇格波导窄带带通滤波器设计及性能分析

基于缺陷态同轴布喇格波导的通带特性,该文采用多波耦合理论及Ansoft HFSS对一种工作频率为60 GHz的新型波导滤波器原型进行了概念性设计,并进行性能分析。结果表明:大尺寸的缺陷态布喇格滤波器在高频工作时,主模与竞争模式之间的寄生耦合会破坏通带结构;当波纹幅度引入汉明窗分布,可以有效地消除这一负面影响。该滤波器具有通带窄(相对带宽小于0.1%)、中心插入损耗小(低于1.5 dB)、结构横向大尺寸大(半径7~10 mm)的优点,能够适用于毫米波段高功率应用场合中对窄频带信号选择。     

单基三电极石英晶体谐振器频率-温度特性研究

设计了一种新型的单基三电极石英晶体谐振器，并在大气环境条件下测试分析了这种谐振器的频率-温度特性，验证了其频率-温度特性与已有的单基单电极谐振器的频率-温度特性基本一致，曲线为三次曲线。在相同激励及环境条件下，在同一基片上设置多对电极时，各对电极构成的谐振器的频率-温度特性基本相同。根据这种相似特点，将同一基片上不同电极对应的谐振器的振动频率进行差频补偿，可有效地抑制温度对谐振器振动频率的影响。这种谐振器所采用的差频补偿方法可为石英谐振器相关特性的进一步开发利用提供依据。研究了这种结构的石英晶体谐振器的晶片表面处理（是否抛光）及边沿形状（是否倒边）对其频率-温度特性的影响。实验结果表明，对单基多电极石英晶体谐振器的晶片表面进行抛光并对边沿进行倒边处理后，谐振器的稳定性得到了有效的改善，性能得到了优化。     

单基三电极石英晶体谐振器频率-温度特性研究

设计了一种新型的单基三电极石英晶体谐振器,并在大气环境条件下测试分析了这种谐振器的频率-温度特性,验证了其频率-温度特性与已有的单基单电极谐振器的频率-温度特性基本一致,曲线为三次曲线。在相同激励及环境条件下,在同一基片上设置多对电极时,各对电极构成的谐振器的频率-温度特性基本相同。根据这种相似特点,将同一基片上不同电极对应的谐振器的振动频率进行差频补偿,可有效地抑制温度对谐振器振动频率的影响。这种谐振器所采用的差频补偿方法可为石英谐振器相关特性的进一步开发利用提供依据。研究了这种结构的石英晶体谐振器的晶片表面处理(是否抛光)及边沿形状(是否倒边)对其频率-温度特性的影响。实验结果表明,对单基多电极石英晶体谐振器的晶片表面进行抛光并对边沿进行倒边处理后,谐振器的稳定性得到了有效的改善,性能得到了优化。     

宽带低相位噪声CMOS环型压控振荡器的设计与研究

采用一种环型电路结构,设计了一个1.3GHz宽带线性压控振荡器.采用 TSMC 0.18μm RF CMOS 工艺,利用 CadenceSpectreRF 完成对电路的仿真.结果显示,在电源电压Vdd =1.8 V 时,控制电压范围为 1.0～1.18 V,频率的变化范围为800 MHz～2.1GHz,相位噪声为-105 dBc/Hz@1 MHz.很好地解决了相位噪声与调谐范围之间的矛盾.     

中红外磷锗锌光参量振荡器的参量对比与分析

对国内外中红外磷锗锌光参量振荡器(ZGP-OPO)的参数进行了对比与分析,包括ZGP-OPO晶体尺寸、泵浦源、相位匹配方式、谐振方式、腔形、阈值、中红外输出等方面,并指出国内外中红外ZGP-OPO技术发展方向。     

束缚磁极化子的有效质量与共振频率的关系

采用改进的线性组合算符法和幺正变换方法,研究极性晶体膜中束缚磁极化子的有效质量与振动频率λ的变化关系.得出束缚磁极化子的有效质量均由两部分组成:第一部分是由于电子-体LO声子相互作用所引起的;第二部分则是电子-SO声子相互作用引起的.后者又包含两部分,分别是电子与极性膜中两支表面声子相互作用的贡献.而且当λ＜20×10...     

太赫兹时域光谱技术检测复合材料与金属的脱粘缺陷

基于太赫兹时域光谱技术,提出应用太赫兹脉冲成像技术检测胶接结构中的脱粘缺陷,研究泡沫材料PMI与钢板胶接结构脱粘缺陷的检测.实验采用反射模式,分别对粘合部分与脱粘部分进行数据测试,对比分析发现数据在时域和频域范围均有明显区别.对待测样品进行二维扫描,应用太赫兹时域信号的时间位置幅值、最大值、延迟时间和频域信号不同频点的幅值、所有频点幅值叠加值对待测样品进行成像.研究结果表明基于太赫兹时域光谱技术的太赫兹脉冲成像技术能够检测出泡沫材料PMI与钢板胶接结构的脱粘缺陷;应用太赫兹时域信号的时间位置幅值、最大值、延迟时间和频域信号不同频点的幅值、所有频点幅值叠加值进行成像的结果,均可以分辨出样品的脱粘缺陷;不同的数据信息的成像效果不同.