SAW动态转矩传感器理论计算与推导

动态转矩的测量对于机械传动过程的监测和控制具有重要意义,现有的测量方式大都是有源接触式的测量,多具有接触滑片磨损和测量精度下降等问题。本实验采用声表面波(SAW)技术的动态转矩测量方法。通过分析其工作原理,以典型ST切片石英基体材料为例,推导SAW器件谐振频率与转矩的关系表达式,提出采用差分连接方式来消除温度对于测量结果的影响,并简要分析测量系统的构成与工作原理。     

A resonator mode in linear arrays of silver spheres and cylinders

INTRODUCTION The waveguide properties of linear arrays (chains) of silver nano-particles at optical frequencies are well known (Krenn et al., 1997; 1999; Tretyakov and Viitanen, 2000; Girard et al., 1994; Weber and Ford, 2004). Silver spheres and ellipsoids can support forward or backward waves along the chain depend- ing on their polarization state and the eigenfrequency (Krenn et al., 1999; Tretyakov and Viitanen, 2000; Girard et al., 1994; Weber and Ford, 2004). At com- paratively …     

新型微带双模带通滤波器设计

设计一种新型的微带双模椭圆函数带通滤波器,该结构带有两个方形切角且中心开圆形槽,并用Ansoft电磁仿真软件对该滤波器结构进行仿真。该滤波器在中心频率2.26GHz处,最小插入损耗为0.27dB,通带内在2.22~2.33GHz之间插入损耗小于1dB,在2.25~2.31GHz之间回波损耗大于20dB,3dB相对带宽为7.08%。在通带两侧有3个衰减极点,提高了阻带的抑制能力。研究表明,该滤波器结构能减小滤波器的体积,有利于实现器件的小型化,同时还能有效减小辐射损耗,使滤波器性能更优。     

Research progress on Fabry-Perot resonator antenna

The Fabry-Perot resonator （FPR） antenna has found wide applications in microwave and millimeter waves and recently attracted considerable interest. In this paper, a summary of planar and cylindrical structures, analytic models and research development is presented, and a comparison between these structures and analytic models is made, showing that such analytic models as the FP cavity mode, electromagnetic band gap （EBG） defect mode, transmission line mode, and leaky-wave mode are consistent when applied to analyze this type of resonator antenna. Some interesting topics under recent research, including dual or multi-band, improvement of gain bandwidth, low profile and beam control, are surveyed.     

Novel circularly-polarized ceramic dielectric resonator antenna excited by a corner-cut square patch

A ceramic dielectric resonator antenna excited by a corner-cut square patch for the circularly-polarized operation is introduced. The effect of patch size and cut size is investigated, showing that the resonant frequency of the antenna can be changed by simply changing the patch size. The reflection, axial ratio, and radiation characteristics of the antenna are found. Measurements were carried out to verify the design. The antenna is compact in structure, which is attractive in the application as the satellite communication terminals.     

一种新型宽带环形滤波器设计

本文设计了一种基于带有两个半波长短路调谐枝节的双模环形谐振器的新型宽带滤波器.该滤波器能够在通带两侧各产生一个传输零点,使得滤波器的插入损耗在通带外的衰减非常迅速,从而提高了滤波器的频率选择特性.利用"奇、偶模理论"对双模环形谐振器进行了分析,并给出了传输零点的计算公式.结合传输零点公式和仿真软件设计出了一个中心频率为4.25GHz、3dB相对带宽为45%的宽带环形滤波器.仿真结果表明,该滤波器具有低插入损耗和良好的频率选择性等优点.     

第二通带可调的双通带滤波器设计

研究了一种双通带带通滤波器,构成方法是在等腰直角三角形阶梯阻抗开路环内部通过微带线连接一个三角形贴片。滤波器第一通带的中心频率取决于开路环传输线的长度,第二通带的中心频率由贴片、连接微带线和开路环三者的尺寸共同决定。改变贴片斜边边长,可以调节第二通带的中心频率,同时保持第一通带中心频率和带宽不变。仿真结果验证了设计方法的有效性。     

手表的工作原理

石英表和机械表的工作原理是不同的。石英表的动力来源是电池，所有的石英表内部都装有电池，它为表中的一个石英谐振器和一个集成电路提供能量。大多数石英谐振器的振动频率为32768赫兹(即每秒振动32768次)，也有少数比这更     

一种Ka波段低噪声下变频器组件

介绍了一种用于毫米波系统的下变频器,其中混频器采用了肖特基二极管镜频回收混频结构,振荡器采用了DRO(dielectric resonator oscillator)结构以提高系统性能,以保证在合适的体积内实现较高的频率稳定度.描述了系统中低噪声放大器、混频器、振荡器的性能,用于评估系统链路性能,最后合并制作在单个基片上.根据测试结果,该下变频器的噪声系数在35GHz处1GHz频率范围内小于5dB,单边带相位噪声系数在偏离载波200kHz处达到-70dBc/Hz.由于采用了介质谐振结构,本振的频率稳定度小于60×10-6/℃.