测量谐振器参数的多点法

本文基于谐振器等效电路模型,提出了一种测量谐振器参数的新方法——多点测量法。通过在谐振频率附近多点测量谐振器散射参数的幅值,即由谐振器的谐振特性可以同时确定出谐振器的无载Q值,耦合系数和谐振频率。实际测量证明了该方法具有优良的精度,且便于实现自动化测试。     

高Q微波介质谐振器材料D_5的研究

研制出新型Ｄ５微波介质谐振器材料。该材料为ＡＢＯ３型钙钛矿化合物。化学组成式为Ｂａ（Ｚｒｘ，Ｚｎｙ，Ｔａｚ）Ｏｎ（式中ｘ＋ｙ＋ｚ＝１，ｎ为任意）。该材料具有稳定的工艺特性和良好的微波性能。１０ＧＨｚ下，无载Ｑ值Ｑ０＝９０００，相对介电常数εｒ＝３０，谐振频率温度系数τｆ（１０－６℃－１）在０附近可调。该材料的出现为Ｘ波段乃至Ｋｕ波段微波介质谐振器的应用提供了一种良好的可供选择的材料。     

激光刻蚀实现介质谐振器参数微调的研究

研究提出激光刻蚀加工技术的新方法,实现微波陶瓷介质谐振器的参数微调.首先运用电磁理论推导求解本征值问题的有限元法,利用该方法验证了机械调节谐振器参数存在的缺点,重点研究激光刻蚀微调操作中存在的几种影响因素,获得激光微调参数与谐振频率改变量的关系式.最后用自制相对频率误差小于0.2％的微波介质谐振器验证了激光刻蚀法微调的优势.     

微波立体平面电路谐振器与耦合谐振器的设计

本文根据立体平面电路的短路终端理论，用优化方法，在给定矩形波导尺寸ａ和ｂ，立体平面电路谐振器间的耦合系数ｋ，谐振频率ｆ与平面电路金属片厚度ｔ的情况下，设计出谐振器的其它尺寸。对设计的样品进行测试，其长度与谐振频率（ｌ－ｆ）曲线及耦合系数与耦合宽度（ｋ－Ｗ）曲线的实验值与设计值基本一致。     

微波介质谐振器温度系数的快速检测系统

谐振频率温度系数是微波介质陶瓷材料的重要性能参数之一,文中提出了一种微波介质谐振器温度系数的新型快速检测方法,并介绍了系统的测试原理、电路结构和软件组成。该系统对微波陶瓷材料温度系数进行测量时,所产生的系统误差、人为误差最小,可实现精确和快速检测。     

分层同轴介质谐振器谐振频率特性的研究

本文导出了置于无限平行导体板间和置于屏蔽结构中的任意分层同轴介质谐振器的TE、TM模场分量表达式以及求解TE、TM模谐振频率的一般耦合特征方程。对于同轴(l=3层)介质谐振器进行了深入研究和大量计算,得到了同轴(l=3层)介质谐振器的主模和一些高次模的谐振频率随几何尺寸和介质特性变化的关系曲线和数据表。     

介质谐振器特性的有限元计算

本文应用有限元方法分析和计算了置于空气和不均匀介质中的圆柱形介质谐振器的谐振频率,以及介质谐振器与微带线的耦合参量。计算结果与现有文献的计算结果和实验结果相当吻合。     

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。     

空气阻尼对微谐振器品质因子及其传输函数的影响

振动方向平行于衬底的梳状微谐振器的品质因子在高真空下可以高达10⁵以上.常压下,受空气阻尼影响,品质因子跌落到10²左右甚至更小.为了设计时能对谐振器的品质因子有一个较为精确的估计,本文首先利用纳维尔-斯托克斯近似方法和库特近似方法对常压下的横向振动谐振器的阻尼功耗进行了估算.同时谐振器作为电路元件,阻尼等效于电路中的电阻,直接影响器件的传输函数,因此本文又建立了该种谐振器的集总参数网络,研究了阻尼对传输函数影响。其结果对横向振动微谐振器的设计有一定意义.     

A Sensitive Method for Measuring Complex Permittivity with a Microwave Resonator

The proposed method was carried out to make easier dielectric studies em powders under controlled pressure when the frequency varies. A TE/sub 01n/-mode resonator is needed. The substance under test is contained in a tube of quartz, placed along the axis of a cylindrical cavity. The mathematical formulation for the complex permittivity is given in rigorously accounting for the presence of the tube. Typical ditticulties are discussed, and experimental results given. The absolute precision of the measurement can be compared with that of the classicrd method (/spl plusmn/2 percent for /spl epsi/' and /spl plusmn/ 10 percent for /spl epsi/'). The greatest error arises from an insufficiently precise determination of the geometrical and electrical characteristics of the quartz tube. This error is systematic, and thus it is possible to demonstrate the very small permittivity variations (/spl plusmn/ 0.3 percent for /spl epsi/' and /spl plusmn/ 5 percent for /spl epsi/').     

一种微波介质谐振器复介电常数测试方法

介绍了一种简单的微波介质谐振腔的设计及性能参数的计算方法，给出了相对介电常数ε1、介质损耗tan δ的详细求解方程，为微波介质陶瓷性能参数的测量提供了一种简单而有效的方法。     

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.     

一种求解微波介质谐振器复介电常数的方法

根据微波谐振系统中电场的波动方程,采用复频率和有耗导体的边界条件,导出以被测介质的复介电常数为本征值的微分和变分方程。使用MATLAB软件中的PDE工具箱,只要是能以二维形式作图表现的微波介质谐振器,都可以求解出其复介电常数,且与实验数据及不同方法计算的结果相吻合,该方法适用面广、计算精确、简洁方便。     

A Graphical Method for Measuring Dielectric Constants at Microwave Frequencies

This paper describes a graphical method for measuring the real and imaginary parts of the dielectric constant epsilon/epsilon/sub 0/ = epsilon' - j epsilon" of materials at microwave frequencies. The method is based on the network approach to dielectric measurements proposed by Oliner and Altschuler in which the dielectric sample fills a section of transmission line or waveguide. In contrast to their method, the network representing the dielectric sample is analyzed in terms of the bilinear transformation Gamma'=(aGamma+b)/(cGamma+d); ad-bc=4. The analysis proceeds from the geometric properties of the image circle in the r plane obtained by terminating the output line in a calibrated sliding short. The technique described retains the desirable features of the network approach but avoids the necessity of measuring both scattering coefficients. As a result the procedure is more direct and, in the case of the TEM configuration, leads to an entirely graphical solution in which the complex dielectric constant can be read from a Smith chart overlay.     

MEMS微波谐振器

南京电子器件研究所采用微机械工艺和硅衬底集成波导技术成功研制出了Q值大于180的单片集成M EM S微波谐振器。该谐振器采用SIW(衬底集成波导)技术形成单片硅填充腔体结构。采用通孔阵列和地平面形成NRD(不辐射介质)波导。主要使用ICP深刻蚀技术形成M EM S通孔。采用CPW电流探针与腔体间进行耦合。研制出的谐振器工作于主模TE101模式,设计中心频率在K波段。使用A g ilent 8510C矢量网络仪在片测试系统进行测量,结果如下:插损小于3.5 dB,带宽小于1.7%,无载Q值大于180,中心频率实际测量结果与设计值误差小于2.5%。芯片尺寸4.7 mm…     

A Dielectric Resonator Method of Measuring Inductive Capacities in the Millimeter Range

A novel technique for the measurement of dielectric and magnetic properties of a homogeneous isotropic medium in the range of approximately 3 to 100 kmc is described. An accuracy of /l.chemc/ 1 per cent is possible in the determination of permittivity or permeability in those cases where the loss tangent is sulliciently small. The measuring structure is a resonator made up of a right circular cyndrical dielectric rod placed between two parallel conducting plates. For measurement of permittivity two or more resonant TE/sub onl/ mode frequencies are determined whereas for the measurement of permeability two or more resonant TM/sub onl/ mode frequencies are determined. The dielectric or magnetic properties are computed from the resonance frequencies, structure dimensions, and unloaded Q. Since the loss tangent is inversely proportional to the unloaded Q of the structure, the precision to which Q is measured determines the accuracy of the loss tangent.     

General Coupling Matrix Synthesis Method for Microwave Resonator Filters of Arbitrary Topology

This letter presents a new approach to synthesize the resonator filters of an arbitrary topology. This method employs an optimization method based on the relation between the polynomial coefficients of the transfer function and those of the S₂₁ from the coupling matrix. Therefore, this new method can also be applied to self‐equalized filters that were not considered in the conventional optimization methods. Two microwave filters, a symmetric 4‐pole filter with four transmission zeros (TZs) and an asymmetric 8‐pole filter with seven TZs, are synthesized using the present method for validation. Excellent agreement between the response of the transfer function and that of the synthesized S₂₁ from the coupling matrix is shown.     

A Microwave Method for Measuring Changes in Lung Water Content: Numerical Simulation

A numerical procedure to simulate several physiological and geometrical changes occurring during development of edema and to study their effects on the sensitivity of the microwave detection method is presented. The method of solution utilizes a model which consists of a two-dimensional cross section of a thorax. The model is based on an X-ray CAT scan taken with the microwave applicators in place. The electromagnetic boundary value problem is then solved numerically using the method of moments. Numerical results are presented to show the effects of several parameters, such as the uneven water distribution in the lung, the field distribution in the aperture of the microwave transmitter, and the location of the receiver on the sensitivity of the microwave detection method. Based on these results, several suggestions are made to help optimize the sensitivity of the microwave method of measuring changes in lung water content.