片式多层陶瓷微波谐振器

介绍了片式陶瓷微波谐振器的工艺过程、谐振器的结构以及结构对谐振器参数的影响,谐振器与外电路的耦合采用耦合间隙的方法与谐振单元在同一层内实现,这种新结构既可给制备工艺带来方便,又可减少工艺所带来的误差。用多层陶瓷工艺技术,用高介电常数、低温烧结微波陶瓷实现了中心频率为1GHz,有载品质因数大于80的试验双端口多层微波谐振器。微波谐振器体积小,整个谐振器的尺寸为7mm×2mm×1mm,适用于表面贴装技术。     

电容式RF MEMS谐振器

介绍了应用于通信领域的电容式RF MEMS谐振器及其在通信系统小型化中的优势。对电容式微机械谐振器进行了综合分析,包括基本工作过程分析、基本参数的理论分析及等效电路的分析。介绍了目前几种常用结构的谐振器,包括梳状谐振器、梁式谐振器及盘式谐振器的工作过程和谐振频率的发展空间。重点分析了谐振器的电容间隙及锚这两个重要的结构参数对谐振器性能的影响。最后,对电容式微机械谐振器存在的问题作了总结,对其发展趋势做出展望。     

《电磁介质谐振器理论》

本书较为系统和全面阐述了电磁介质谐振器和谐振结构,用近代计算电磁学和网络的方法,对各种谐振器和谐振结构的电磁参数和网络参数进行系数的分析计算。本书共分九章,约60万字,即:均匀媒质中的弧立介质谐振器,两平行导体板间的介质谐振器,金属波导和空腔中的介质谐振器,准光谐振结构,激励与耦合,谐振器网络,介质谐振器无     

超小型微带带通滤波器

低损耗带通滤波器是有线和无线宽带通信必不可少的。但遗憾的是,基于1/2波长耦合谐振器的微带带通滤波器往往要求很大的面积,从而限制了它在便携式和手持装置中的应用。为了克服这一障碍,台湾新化教育大学的研究人员开发了一种取代传统微带带通滤波器的方法。他们采用三角形开环谐振器和一种折叠线形缺陷接地结构,使得滤波器的尺寸达到最小。通过恰当地选择上述谐振器馈线的抽头部位,所产生的传输零就可被正确地探测出,以改善滤波器的边缘抑制。他们用Rogers公司相对介电常数为10.2的RT/Duroid6010.2衬底材料制造了一个样品滤波器,该滤波…     

一种新型谐振式微加速度计设计和分析

为提高谐振式加速度计的灵敏度,设计了基于两级微杠杆机构和DETF谐振器的新型谐振式微加速度计结构;用解析法分析了加速度计灵敏度和结构各参数之间的关系,并以此对结构参数进行了优化设计。理论计算表明,所设计的加速度计灵敏度约为56Hz/g;由有限元仿真分析也得出了相似的结论。     

一种新型圆柱形介质谐振器微带天线仿真分析

在叙述圆柱形介质谐振器及其频率特性的基础上,通过基于有限元法的高频结构仿真软件Ansoft HFSS 12仿真,获得圆柱形介质谐振器半径与高度变化对天线工作带宽和增益的影响,得到驻波关系曲线图。通过分析仿真结果,得出在R_c=2.9 mm,H_c=4 mm时天线性能最佳,优化的圆柱形介质谐振器的参数有利于提高天线的性能。     

一种新型谐振式微加速度计设计和分析

为提高谐振式加速度计的灵敏度,设计了基于两级微杠杆机构和DETF谐振器的新型谐振式微加速度计结构;用解析法分析了加速度计灵敏度和结构各参数之间的关系,并以此对结构参数进行了优化设计.理论计算表明,所设计的加速度计灵敏度约为56 Hz/g;由有限元仿真分析也得出了相似的结论.     

一种新型谐振式微加速度计设计和分析

为提高谐振式加速度计的灵敏度，设计了基于两级微杠杆机构和DETF谐振器的新型谐振式微加速度计结构；用解析法分析了加速度计灵敏度和结构各参数之间的关系，并以此对结构参数进行了优化设计。理论计算表明，所设计的加速度计灵敏度约为56Hz/g；由有限元仿真分析也得出了相似的结论。     

片式压电陶瓷谐振器的研制

世界组装技术的新发展,要求元器件片式化,本课题就是研制片式压电陶瓷谐振器。是在插脚式配方的基础上,用Mg、Ca等离子取代Pb,并掺入Ce、Mn等杂质,以提高居里温度。采用气流粉碎法、热压烧结、厚度切变模及叠层封装结构,以利于稳定性和片式化。最终研制出频率精度高、温度特性好的片式压电陶瓷谐振器。     

基于并行FDTD方法分析表面等离子波导的特性

设计了一种双L形表面等离子体矩形环谐振器波导,采用并行时域有限差分方法,对这种波导的传输特性随几何结构参数的依赖关系进行了分析.计算结果表明通过改变输入/输出光波导的结构参数,可以调节该波导的消光比和频率选择特性.该波导结构能够有效地抑制后向辐射干扰并且大幅度地提高其场消光比,这使得此类谐振器结构更具有功能性.     

气隙设计对电感绕组损耗的影响

鉴于绕组区域处的磁场分布对高频磁性元件的铜损影响很大,利用有限元分析,研究了气隙在磁芯柱位置对铜箔绕组和漆包线绕组铜损产生的影响,以及分布气隙参数对绕组铜损的影响。结果表明:气隙在磁芯柱位置对铜箔和漆包线绕组的铜损影响不同。在分布气隙设计中,气隙之间的距离大于5个气隙长度时,气隙之间的影响可以忽略。分布气隙个数的选择,应该使绕组到气隙的距离大于3个而不超过5个气隙的长度。     

Lagrangian formulation of a linear microstrip resonator: theory andexperiment

A Lagrangian approach is used to formulate the electromagnetic scattering properties of a linear microstrip resonator. The resonator design includes a center microstrip separated from the source and output loads by dielectric gaps. The gaps of the resonator are represented by capacitively coupled π-networks whereas the Lagrangian is formulated in the discrete limit such that the equations of motion transform into two boundary conditions, relating the waves on the two sides of the gap in terms of two lumped capacitors. The effective capacitors expressed in the boundary conditions are actually the capacitances experienced by the even and odd excitation modes of the system, respectively. The calculations, therefore take into account the characteristic impedance, effective dielectric constant, conductivity of the metal strip and the ground plane, and dielectric loss tangent of the dielectric material. In addition, the two capacitor values representing the gaps are included in a consistent manner with the above parameters by the application of the Lagrangian formulation. Calculated and measured reflection coefficients of linear microstrip resonators are compared, and general agreement is found between theory and experiments     

Micromechanical resonators with submicron capacitive gaps in 2 μm process

An innovative gap reduction technique is reported to achieve sub-micron capacitive gaps for micromechanical resonators to boost the output signal using the standard low-cost 2 mum commercially available foundry process from MEMSCAP. Electrostatic actuation was used to reduce the gap size below the fabrication limitation. To demonstrate the proposed idea, a 6.35 MHz Lame-mode square resonator was designed, fabricated and tested. The resonator gap size was experimentally measured to be 0.64 mum, which boosted the resonance peak by 20 dB.     

Intercomparison of permittivity measurements using thetransmission/reflection method in 7-mm coaxial transmission lines

Broadband permittivity measurements made by eleven organizations using the transmission/reflection (T/R) method are compared to high-accuracy cavity resonator results. T/R accuracy is less than 10% for ϵ_r^'<15, and the smallest measureable loss factor is ϵ_r^"≈0.05. Uncertainty caused by the air gaps between the specimen and the inner and outer conductors is the largest contributor to the overall uncertainty. Compared to other dimensional measurement methods, physical measurement of specimen bore and outer diameters yield the most accurate gap corrections     

Omnidirectional Single-negative Gap and in Fibonacci Sequences Composed of Single-negative Materials

The band structures of Fibonacci sequence composed of single-negative materials are studied with a transfer matrix method. A new type of omnidirectional single-negative gaps is found in the Fibonacci sequence. In contrast to the Bragg gaps, such an omnidirectional single-negative gap is insensitive to the incident angles and polarization, and is invariant upon the change of the ratio of the thicknesses of two media. It is found that omnidirectional single-negative gap exists in the other Fibonacci sequence, and it is rather stable and independence of the structure sequence.     

Single-spark ring transmitter

A novel type of spark transmitter using a circular arrangement of capacitors alternating with spark gaps was described previously. (K. Landecker and K. S. Imrie, "A novel type of high power pulse transmitter," Aust. J. Phys., vol. 13, 1960, pp. 638-654.) The circular array was arranged such that it formed an oscillating magnetic dipole radiating RF power directly without the use of additional radiating elements. It has now become possible to achieve the same result with the aid of a single-spark gap either by incorporating distributed circuit elements, essentially half-wave transmission lines acting as 1 to -1 transformers, into the arrangement, or by assembling the array of tightly coupled individual tuned circuits having a common single-spark gap. It is shown that the latter arrangement is superior to the use of distributed circuit elements. This results in a very great simplification of the design because the question of synchronization of a multiplicity of spark gaps does not arise. It is finally shown that the capacitors distributed equidistantly around the circumference of the transmitter may advantageously be replaced by one single ring-shaped capacitor.     

Frequency-selective properties of a microstrip filter with irregular dual-mode resonators

Frequency-selective properties of a microstrip filter containing dual-mode hairpin resonators with a stepwise change in the width of the stripline conductor whose one end is connected to the screen are studied. Dependences of the design parameters and the steepness of the slopes of the amplitude-frequency response of a two-resonator filter on the filter fractional bandwidth and the substrate permittivity are considered. A large domain of the anomalous behavior of the gaps between the resonator conductors, in which the gap increases with the width of the filter passband, is revealed. The domain of values of the fractional bandwidth and the frequency band in which the design parameters of the device are realizable are determined. Good agreement between the results of the quasi-static calculation and experimental results is demonstrated.     

Ultrafast Relaxation of Charge Carriers Induced Switching in Terahertz Metamaterials

We demonstrate ultrafast switching of resonant mode in terahertz metamaterials through optical excitation of radiation-damaged silicon placed in the gap of a split-ring resonator. Upon optical excitation, we observe the dynamic transition of the fundamental resonance from ON-to-OFF state on a timescale of 4 picoseconds (ps) and then fast recovery of the resonance to the ON-state within the next 20 ps. Electric field distributions in the metamaterial unit cell derived through numerical simulations clearly support our experimental observations, showing that the high electric field at the resonator gaps, responsible for inductive-capacitive (LC) resonance, completely disappears and switches OFF the resonance after being optically excited. The ultrafast switching of the metamaterial resonance is attributed to the relaxation of the photo-carriers through the defect states of radiation-damaged silicon layer. Such ultrafast material–based active control of metamaterials can lead to the ultrafast terahertz metaphotonic devices.     

激光致盲干扰效能分析研究

为了分析研究激光致盲干扰的作战能力,评估激光致盲干扰的作战效能,基于激光致盲干扰的干扰原理和干扰效果评估准则,采用效能评估分析方法,总结出激光致盲干扰的干扰方程,从干扰方程出发,提出了致盲距离、致盲概率两个效能分析指标,给出了概念、计算模型,并进行了理论分析和仿真验证。结果表明,激光干扰机的输出功率越高,光束质量越好,致盲距离就越大;激光干扰机的定位精度越高,致盲概率就越大,从而分析总结出影响激光致盲干扰效果的因素,为激光致盲干扰研究奠定了基础。     

周期性压电分流阵列板带隙特性研究

将带有分流电路的压电片周期性地粘贴到薄板表面形成二维压电分流阵列结构,该结构不仅具有声子晶体的带隙特性,还可以通过分流电路实现带隙调控。该文运用有限元法计算了二维压电分流阵列结构的带隙特性,研究了含有谐振单元及负电容的混合电路中不同电路参数对带隙的影响。此外,通过调节电感及负电容,可以将布喇格带隙和局域共振带隙进行耦合,拓宽带隙,实现宽频振动控制。