Study of Spatial Distribution of Piezoelectric Properties of ZnO Films by Acoustic Resonator Spectroscopy

Using broadband acoustic resonator spectroscopy, an almost twofold increase in the frequency of optimal excitation of the composite microwave resonator of shear bulk acoustic waves is found when the distance from the substrate to the magnetron axis during the deposition of a ZnO film by magnetron sputtering is changed. The frequency characteristics of the resonator structure are simulated and an explanation of the change in the optimal excitation frequency by the inhomogeneity of the inclination of the ZnO film texture’s axis over the thickness is proposed.

     

Bistability in a nonlinear magnetoacoustic resonator

The characteristics of a nonlinear magnetoacoustic resonator are studied. The resonator is fabricated from an antiferromagnetic hematite (α-Fe₂O₃) monocrystal. The amplitude-and phase-bistability loops are investigated experimentally when an exciting signal has a cyclically variable frequency and a fixed power or a cyclically variable power and a fixed frequency. Bistability is induced by strong coupling between the acoustic and magnetic subsystems of hematite. This coupling results in renormalization of both linear and nonlinear elastic moduli of the crystal and causes the resonator frequency to depend on the external magnetic field and the power level of the exciting signal. At low power levels, the resonator’s transmission characteristic is a Lorentzian curve and the frequency can be tuned over an interval of 65% of the initial value as the field ranges from 0 to 3 kOe. An increase in the signal power results in a distortion of the characteristic and in the frequency shift of the maximum transmission factor by 2.1%. Analytical expressions for the amplitude and phase bistable characteristics of a nonlinear magnetoacoustic resonator are obtained. Calculated and measured data are in quantitative agreement.     

具有带通响应的槽线微波功分器

首次提出一种基于半波长槽线谐振器的功分器。该功分器集合了功率分配、带通响应这两种功能于一身,实现了电路设计的多功能化和小型化。该功分器的仿真和测试结果吻合良好,在通带内功分器的两个输出端口3dB等分同时插入损耗小于2dB。区别于传统功分器的是,该功分器两个输出端口的在基波同相,而在二次谐波处为反相信号。这个特点在微波非线性电路的功率合成过程中可用来抑制二次谐波。     

基于折叠型SIR 谐振器的双通带滤波器设计

文中提出了一种基于折叠型SIR 谐振器的双通带频率可控的微带滤波器,它由SIR 谐振器特性结合 传输线理论实现。该滤波器设计为具有两个自由度,调节谐振器的导带宽度可以对两个通带之间的频率及其间隔 进行调节。文中还研究了调整谐振器导带长度对滤波器频率特性的影响。测试结果表明,该微带滤波器有两个通 带,其中心频率分别为2. 79 GHz 和3. 90 GHz,带内最小插入损耗分别为-0. 96 dB 和-3. 0 dB,带内最小回波损耗分 别为-42 dB 和-18 dB,相对带宽分别为5. 7%和6. 7%。仿真和测试结果的一致性证实了滤波器设计的有效性。     

鼓形AT-切石英谐振器的力频特性

讨论了鼓形ＡＴ－切石英谐振器的力频特性。理论基础是初始有限变形上叠加弹性增量变形,并且使用了Ｍｉｎｄｌｉｎ所提出的把应变应力展开成板厚的级数的方法。在把三维运动方程简化为二维运动方程后。推导了带有电极的ＡＴ－切石英谐振器的运动微分方程。为了得到鼓形ＡＴ－切石英谐振器的Ｒａｔａｊｓｋｉ系数,在计算石英片在初始应力作用下的应力应变分布时考虑了石英各向异性的特性。将计算结果与其他研究者的实验和理论结果进行了比较。     

有源波导环形谐振腔产生毫米波的理论分析

提出了一种用有源波导环形谐振腔产生毫米波的方案。阐述了用有源环形腔产生毫米波的基本原理,分析了泵浦光功率、泵浦光持续时间和输入到环形腔中的光脉冲宽度对产生的毫米波性能的影响。分析结果表明当该方案用于ROF中产生射频波段的毫米波,以及用于高频微波光子技术中优势显著。     

Design of a multicoupled loop-gap resonator used for pulsedelectron paramagnetic resonance measurements

The purpose of the present paper is to establish a method of design for a multicoupled loop-gap resonator used for pulsed electron paramagnetic resonance measurements. For the design of resonator characteristics, the method has an advantage of a systematic approach without iterative calculations. In this design, the number of loop-gap resonators used is first determined from the pass band required as the specifications of the resonator. To satisfy the specifications, electrical parameters of an equivalent circuit and the dimensions of the resonator are estimated. By the proposed method, a prototype resonator which has the operation frequency of 1.3 GHz is designed and fabricated. For the prototype resonator, the characteristics of the return loss agree with the required ones. As a result, the validity of the design method is experimentally confirmed     

Gunn-Diode Oscillators and Amplifiers Based on the Barrel-Shaped Open Resonator

An open resonator with its constituent the barrel-shaped reflected surface is described. Millimeter wave-band oscillator and amplifier based on this resonator investigated. The power and frequency characteristics are presented. It is shown that this device can best be used as a regenerative amplifier.     

两种小型谐振器在微带均衡器中的应用

本文阐述了新型发卡式谐振器和矩形螺旋形谐振器及其在微带均衡器中的应用,利用上述两种谐振器分别设计了两种微带均衡器单子结构电路,通过仿真发现采用新型发卡式谐振器的均衡器单子结构电路具有频率调谐功能;而采用螺旋形谐振器的均衡器单子结构电路不仅具有频率调谐功能,而且具有衰减幅度调节功能,解决了由于实际加工误差引起的频率和衰减偏移问题。最后根据实际需要采用这种螺旋形谐振器设计了一个微带均衡器并给出了其频率曲线。     

The Radiation of Electromagnetic Power by Microstrip Configurations

A new technique for calculating the radiation losses of microstrip configurations is presented. The method applies if the wavelength is large compared to the width of the conducting strip and the thickness of the dielectric wafer. It is shown that the radiated power, which is partly carried by "space waves" and partly by "surface waves," can be computed in terms of the specific inductance and the specific capacitance of the transmission line, without making any assumptions regarding the current distribution in the microstrip. It appears that the fraction of the radiated power carried by surface waves contains the frequency to a higher power than does the fraction carried by space waves and is therefore relatively small. The investigated configurations are the infinitely long transmission line excited by a voltage-slit, the half-wavelength straight resonator, the full-wavelength circular resonator, and the quarter-wavelength hair-pin resonator. It follows that the quality factor of the straight resonator and the circular resonator are inversely proportional to the square of the frequency, whereas the quality factor of the hairpin resonator is inversely proportional to the fourth power of the frequency.     

Finite-difference analysis of dielectric-loaded cavities using thesimultaneous iteration of the power method with the Chebyshevacceleration technique

A numerical procedure using the finite-difference technique, simultaneous iteration based on the power method, and the Chebyshev-polynomial preconditioning is proposed to analyze dielectric-loaded cavities. The merit of this method is that no matrix inversions are invoked and the convergence rate of the power method is greatly accelerated by the preconditioning. The TE, TM, and hybrid modes in axisymmetrical cavities loaded with a rod or ring dielectric resonator are analyzed. For the hybrid modes, an H_r-H_z formulation is proposed. Accurate numerical results are obtained efficiently and no spurious solutions are found by the present method     

压电谐振器特殊模态振动特性研究

针对压电谐振器振动特性分析的应用需求,构建了一种小型化、廉价的矢量分析系统。系统采用STM32控制4路DDS芯片产生驱动信号和矢量解析正交信号。通过向DDS芯片写频率控制字,对压电谐振器进行扫频驱动。同时采用STM32内置ADC,采样并计算获取各频率点压电谐振器输出信号的幅值和相位。通过提取压电谐振器两个特殊振动模态下的共振频率、品质因数(Q值)、输出信号相位等振动特性参数,获得驱动信号对这些参数的影响规律,系统分析了驱动信号对压电谐振器振动特性的影响,为压电谐振器的驱动、信号检测提供了有效的技术途径,实验结果为压电谐振器振动特性分析提供了依据。     

基于谐振器慢波传输线的小型化宽阻带谐波抑制功分器

该文提出一种基于谐振器慢波传输线的小型化宽阻带谐波抑制功分器,该谐振器慢波传输线由矩形谐振器、T型谐振器和蛇形线构成,来取代功分器中的1/4波长传统微带传输线。所设计制作的功分器,其尺寸仅为传统微带功分器的37.4%。实验结果表明,该功分器回波损耗大于10 dB的带宽范围为0.1～1.19 GHz,在2.2～11.05 GHz频率范围内衰减大于20 dB,具有较宽的阻带从而具有抑制谐波效果。仿真和测试结果较为吻合,验证了所提设计方法的有效性。     

Dual-mode stepped-impedance ring resonator for bandpass filterapplications

It is well known that two orthogonal resonant modes exist within a one-wavelength ring resonator. In this paper, we focus on a ring resonator possessing an impedance step as a form of perturbation. A convenient analyzing method for obtaining the resonance characteristics of this resonator structure is presented. Furthermore, generation of attenuation poles obtained by the dual-mode ring resonator is discussed. In addition, a filter design method based on this resonator is explained, followed by experimental results, which prove the validity of the proposed design method     

A study on the performance of a gyromonotron

A method is presented which allows to calculate the large signal beam efficiency of a gyromonotron working at the s-th harmonic of the cyclotron frequency. The results of this calculation using efficiency optimized parameters are given for different TE_mn distributions and also for a magnetic taper. It is shown that beam efficiencies, which are higher than twice the value at constant electric and magnetic fields are theoretically possible. Also the influence of the beam voltage is considered. For a given beam voltage and a given electric field distribution in the resonator power calculations are performed and it is shown what powerlevels are available for different resonator modes and for different cyclotron harmonics.     

Comparison Decrement Method for Microwave Resonator Q Measurements

The sensitivity of resonator quality-factor measurements using the decrement method can be improved by the comparison of the decay curve of a measured resonator with that of a reference standard resonator. The decay curves are compared using the integral of the function given as difference between decay curves. The comparison method, to be proposed, also has the advantage that the calibration of neither time base nor power scale is needed. Some results of the experimental verification are presented.     

Microwave binstability in a planar ferrite-piezoelectric resonator

Bistability in a planar resonator containing an iron-yttrium garnet ferrite film and a lead zirconate titanate (PZT) plate is studied. The characteristics of the bistable resonator are measured in a frequency band of 0.8–16 GHz at an excitation power level ranging from 1 to 20 mW. Magnetic and electric tuning of the resonator frequency and switching of the resonator between stable states with the use of weak magnetic (∼0.5 Oe) and electric (0.75 kV/cm) fields are demonstrated. It is shown that, as the excitation power increases, the resonator’s switching time decreases from ∼1.7 to ∼0.3 μs.     

基于枝节加载开环谐振器的带阻滤波器设计

提出了一种具有良好谐波抑制功能的双枝节加载开环谐振器,加载枝节采用均匀阻抗结构,与同尺寸的开环谐振器相比,结构更紧凑,能够更好地抑制寄生模,而且可以达到更低的谐振频率。分析了加载枝节参数对带阻滤波器抑制二次谐波的影响。通过在加载的双枝节间引入集总可变电容,可以使谐振器具备谐波抑制性能的同时,实现中心频率可调的功能。基于双枝节加载环谐振器设计出一种可调带阻滤波器,中心频率可以在900MHz ~2. 65GHz 范围内调节,而且最低寄生阻带能够抑制到8GHz。     

多棒平行平面腔动态工作特性的研究

基于等价腔方法,将高功率固体激光器使用的二棒平行平面腔的结果推广到多棒平行平面腔。推导出了g*参数和等价腔长的解析表达式。对这类光腔的动态工作特性做了详细分析,并给出了数值计算例。研究表明,对两类多棒对称平行平面腔,在g*参数图上的动态特性曲线是过原点的一条直线。若多棒的热焦距有小的偏差,特性曲线不再是直线。然而,用适当调节镜和棒以及棒间距离的方法可以使特性曲线重新成为一条直线。因而采用这种方法可以补偿棒的热焦距偏差,给出了有关的数学公式。     

基于能陷理论的石英力敏谐振器集群的设计

石英谐振器可以作为传感器的敏感元件。为了减小温度等因素的干扰,提高石英晶体谐振器力敏特性,通过能陷理论及其厚度剪切石英晶体谐振能量分布曲线的计算,在同一圆形晶片上设计了多电极力敏谐振器集群。根据共模抑制原理,将谐振器集群输出频率信号作差频处理,以此抑制温度等因素的干扰,再将差频信号叠加以提高石英晶体谐振器集群整体力敏特性。实验结果表明,石英谐振器集群差频输出的温频特性明显优于传统的单电极谐振器,石英晶体谐振器集群整体力灵敏度系数提高到9 992 Hz/N。