Analysis of Millimeter Wave Varactor-Tuned Gunn Oscillator Stabilized with a Transmission Cavity

A novel circuit architecture which describes millimeter wave varactor-tuned Gunn oscillator stabilized with a transmission cavity has been proposed in this paper. A corresponding equivalent circuit model has been presented in order to study its performance characteristics. The circuit model consists of four parts which are varactor cavity, main cavity, transmission waveguide and transmission cavity. Based upon this model, electrical tuning characteristics have been studied at first. Mode jumping problems during electrical tuning process have been analyzed qualitatively. Moreover, quality factor and efficiency of the circuit model have been derived by virtue of relevant circuit parameters. The effects of some important circuit parameters affecting circuit performance parameters have been discussed. The circuit model can describe the circuit architecture accurately and effectively. This circuit architecture, which can generate signals exhibiting low frequency modulation noise, high frequency stabilization and electrical tunable characteristics, is applicable to various practical situations.     

Simulation Investigation of Millimeter Wave Varactor-tuned Transmission Cavity-stabilized Oscillator

A new circuit configuration for millimeter wave varactor-tuned transmission cavity-stabilized oscillator has been proposed in this paper. Compared to conventional varactor-tuned reflection cavity-stabilized oscillator, in this configuration, a high quality factor transmission cavity directly coupled to varactor diode is employed to improve the performances of the oscillator. The operation frequency of this oscillator can be tuned by varying the resonant frequency of the transmission cavity through changing bias voltage of the varactor diode. An equivalent circuit model for the oscillator has been presented in order to theoretically investigate the performance characteristics of the oscillator. On the basis of this model, electrical tuning characteristics have been studied. Mode jumping phenomena during electrical tuning process have been analyzed for obtaining stable operations of the oscillator. The analytical formulae of quality factor and efficiency have been derived in terms of relevant circuit parameters. Particular emphasis has been paid on several circuit parameters which have a substantial impact on circuit performance. Some design considerations have been pointed out according to the simulation results, which are useful to the design and fabrication of this type of oscillators.     

Cavity Stabilized X-Band Gunn Oscillator

The design and resultant experimental investigation of a pulling mechanism for a highly stable X-band Gunn oscillator, stabilized by a high Q TE/sub 011/-mode reflection cavity, are described. The oscillator shows a temperature coefficient of less than -7 x 10/sup -7/ / /spl deg/C,a low FM noise of 8 Hz per 1-kHz BW at 100 kHz from the carrier, and a wide-band mechanical-tuning capability of several hundred megahertz. In addition, experimental results concerning the hysteresis phenomena of oscillating frequencies, power, FM-noise versus cavity-pulling frequencies, and bias voltages are described.     

Proposal for a Tunable Millimeter Wave Molecular Oscillator and Amplifier

An atomic beam apparatus suitable for a millimeter wave generator is theoretically discussed. The beam consists of atoms having a net magnetic moment. The upper and lower Zeeman levels of the atomic beam in a magnetic field are spatially separated by an inhomogeneous magnetic field. The upper state atoms enter a cavity where transitions occur at a frequency determined by a static magnetic field. The resonant frequency of the cavity is set at the transition frequency. The positive feedback of the cavity allows operation as an oscillator. Some of the more important parameters for oscillator operation are evaluated.The upper frequency limit is determined primarily by the resonant structure design.     

Millimeter Wave Diodes for Harmonic Power Generation

A discussion of the application of point contact, electrically formed semiconductor junctions to harmonic generating applications is presented. Three different combinations of materials are considered. First, the more popular phosphor-bronze point on gallium arsenide combination is discussed. Results with this material combination when used as millimeter wave multipliers are given as a reference point. The combination n-GaAs/Cu is then examined. The slope parameter of these diodes shows that the junction is very close to that of a Schottky barrier. The conversion efficiency measured for these diodes shows a 2 to 4 dB improvement over the n-GaAs/P-Br diodes. The third combination, and by far the most efficient, was the n-GaAs/Zn diode. These are true p-n junctions (as opposed to Schottky barriers) and have measured zero bias cutoff frequencies on the order of 1000 GHz. The efficiency realized with these diodes in doubling from 70 GHx to 140 GHz typically ranged from 20 percent to 30 percent. The highest output power at 140 GHz that was measured was 16 milliwatts.     

Millimeter Wave Multi-mode Transmission Line Components

The present paper reports on the recent development of several oversized millimeter wave transmission line components for different applications. The studies include a circular TE₁₁-to-Gaussian beam mode converting horn, a TM₀₁-to-rotating TE₃₁ mode converter, a TE₁₁-mode 90° bend, a series of different HE₁₁-mode transmission line components, a notch filter and a fast laser controlled semiconductor microwave switch.     

Millimeter Wave Band Cavity Resonators for Magnetoresonance Experiments

Electrodynamical features of rectangular cavity resonators as experimental cells of Electron Spin Resonance spectrometer for the millimeter frequency band have been investigated. Measurements and analytical estimations of features of three types of resonators (film-wall type, diffraction grating-wall type, double-wall type) are presented. The advantages and imperfections of each design as well as recommendations for their applications in millimeter wave magnetospectroscopy are given.     

一种低相位噪声的毫米波压控振荡器

基于推推振荡器结构设计了一种低相位噪声的毫米波压控振荡器,相比传统采用直接振荡和倍频实现的振荡器,该振荡器具有体积小、相位噪声低及电路简单等优点.振荡器中的谐振电路采用多级串联谐振,电感采用微带线的形式,提高了谐振器的品质因数,进而降低了振荡器的相位噪声,且在谐振电路通过微带耦合方式实现了基频输出.基于GaAs异质结双极晶体管(HBT)工艺对振荡器进行了设计和流片,芯片尺寸为1.8 mm×1.4 mm.在5V工作电压和0～13 V调谐电压条件下,振荡器的输出频率为42.1～46.2 GHz,电流为120 mA,输出功率为1 dBm,1/2次谐波抑制大于15 dB,相位噪声为-60 dBc/Hz@10 kHz、-85 dBc/Hz@100 kHz和-105 dBc/Hz@1 MHz.     

毫米波腔体滤波器谐振腔平整度误差研究

平整度误差引起的寄生量变化对毫米波滤波器的自谐振频率及品质因数有重大影响,为获得低插损、高品质因数的滤波器结构,针对滤波器制作中存在的平整度误差,该文开展了一系列的研究。通过对基于SU-8胶的毫米波腔体滤波器电铸工艺实验的反复探索,制定出一套能减小毫米波滤波器谐振腔平整度误差的最优电铸方案,即利用脉冲小电流进行电铸。实验结果表明,利用50mA小电流密度电铸能快速获得平整致密高质量的滤波器谐振腔,其铸层表面平整度误差小于2μm;制作精度高,且能实现快速制作。可见,小电流脉冲电铸得到的铸层平整、致密,可有效减小毫米波滤波器的寄生效应,提高系统的精度及灵敏度。     

On the Matching of Transmission Cavity Stabilized Microwave Oscillators

A matching condition is derived for a transmission cavity stabilized microwave oscillator, which takes account for the power loss in the diode mounting structure. In addition, the power dissipated in the damping resistor--which is commonly used in order to eliminate mode jumping problems--is minimized, thus leading to a useful improvement in both output power and loaded Q-factor of the compound oscillator structure. The effectiveness of the design procedure is finally demonstrated by applying it to a Gunn oscillator realization: at 15 GHz a loaded Q-factor of 6500 could be achieved at the sacrifice of only 2.4-dB overall power loss.     

质量和频率随时间变化的谐振子的波函数和压缩态

本文通过一系列的么正变换，得到了质量与频率随时间变化的谐振子系统的波函数，进一步利用此波函数构造了此系统的压缩态，并精确求解了一种特殊的质量与频率随时间变化的谐振子系统。     

Millimeter Wave Gunn Diode Oscillator Design Based on FDTD Method*

In this paper, a millimeter wave Gunn diode oscillator is analyzed and designed by the finite-difference time-domain (FDTD) method. The design results indicate that the oscillator has an oscillation frequency of 45.0GHz and a higher oscillation voltage. Based on the circuit equations and an integral transform, an improved matrix method is utilized for the oscillator design. This method is also extended to model the hybrid network which is constructed by the high order linear elements and the nonlinear elements with arbitrary connections. The experience shows that the improved FDTD method is stable with the time step length Δt based on the Courant condition.     

Dependence of Output Power on Cavity Length in a Gyrotron Backward Wave Oscillator

A relativistic electron beam (500 keV, 200 A, 10 ns) generated magnetically tunable microwave radiation in a frequency range of 9-13 GHz when it is injected into an X-band rectangular waveguide immersed in a uniform axial magnetic field (4-10 kG). The mechanism of the microwave radiation was identified as the gyrotron backward wave interaction. The output power of the radiated microwave increased exponentially with the increase of the cavity length.     

新型慢波系统毫米波行波管研究

研究了三种新型的曲折波导慢波系统,分别是曲折双脊波导、脊加载曲折波导和矩形槽加载曲折波导。给出了其高频特性的理论和仿真结果。然后介绍了基于常规曲折波导和脊加载曲折波导慢波系统的Ka 波段行波管的实验结果。     

Three Dimension Simulation of Millimeter Wave Double Staggered Coupled Cavity Structure

After analyzed the cavity field mean method theory resolution, the software simulation method to obtain the resonance frequency, Q value and RF dispersion by MAFIA and ANSYS software is discussed for the double staggered coupled cavity Millitron structure in the millimeter-wave TWT. The resonance frequency and Q value of the single cavity is obtained and is consistent with two kind of the simulation software. Their average error is about 0.6%. The two kind of the simulation result is consistent to the design precise. The simulation method saves on the cost and time in the experiment, improve the data precise and work efficiency. The trend of the dispersion simulation result is consistent with the cavity field mean method theory result. The high end of the theory result is great contrast to that of MAFIA result. It shows that the theory adopt some hypothetical conditions, But the theory result has some instructional signification in initialization design of the novel slow wave structure.     

毫米波有源柱面共形微带阵列天线的理论与实验研究

本文介绍了一种新型Ｋａ波段毫米波有源柱面共形微带阵列天线,实现了振荡器与天馈系统的单片集成,并应用圆柱坐系下的时域有限差分法对该阵列天线进行了计算和理论分析,得到了令人满意的理论和实验结果。     

毫米波谐波振荡器的Volterra级数分析法

本文基于Ｖｏｌｔｅｒｒａ级数法和非线性转移函数理论，提出了一种分析毫米波谐波振荡器的新方法，给出了描述其非线性特性的决定方程，通过求解一组非线性代数方程，便可计算出谐波振荡器的振荡频率和幅度。文中给出了具体分析实例，并与谐波平衡法等进行了比较，结果表明：这种方法具有理论严密、准确性高、适用范围广等特点，特别是利用一次决定方程的结果作为其它非线性数值分析方法的初始估值，则可大大地节约计算时间，并容易     

毫米波谐波振荡器的多模Volterra级数分析

本文基于Ｖｏｌｔｅｒｒａ级数和非线性转移函数理论，提出了一种分析毫米波谐波振荡器的新方法一多模Ｖｏｌｔｅｒｒａ级数法，并给出了描述其非线性特性的决定方程，通过求解一组非线性代数方程，便可计算出谐波振荡器的振荡频和幅度。文中给出了分析实例并与谐波平衡法等进行了比较，结果表明：这种方法具有理论严密、准确性高，适用范围广等特点特别是利用一次决定方程的结果作为其它非线性数值分析方法的初始估值，可大大地节约     

360 GHz返波管的研究

对采用齿状光栅结构的慢波电路进行了研究,该结构在电子束与光栅表面接近的情况下有一定的通过率。在求得最大耦合阻抗条件下,设计了一种工作在360 GHz的返波管,通过对互作用电路的耦合阻抗的分析,可以减小亚毫米波及太赫兹真空电子学辐射源对阴极发射电流密度的要求。当工作电压为19.5 kV,工作电流75 mA时,PIC模拟结果得到了8 W的平均功率输出,考虑阴极为脉冲工作时,该器件在360 GHz可以得到4 mW的平均功率输出。     

Understanding Soliton Wave Propagation in Nonlinear Transmission Lines for Millimeter Wave Multiplication

In this paper, soliton propagation in nonlinear transmission lines (NLTLs) periodically loaded with symmetric voltage dependent capacitances is studied. From the lumped element equivalent circuit of the line we have analyzed the influence of nonlinear shunt reactances on soliton propagation characteristics. It is shown that by increasing the non linearity of the C–V characteristic, a faster separation of input signal into solitons is achieved. The fact that frequency multiplication in NLTLs is governed by soliton formation makes the results of this work relevant to understand the influence of nonlinear loading devices on multiplier performance. Since a heterostructure barrier varactor (HBV)-like voltage dependent capacitance has been considered for the nonlinear devices, this study can be of interest for the design of millimeter wave frequency multipliers loaded with HBVs.