Effect of structural thickness, anchor length and number of anchors on performance of micromechanical bulk-mode resonators

The performance of micromechanical Lame′-mode square resonator designs with different geometric parameter variations in structural layer thickness, length of anchor beams and the number of anchors placed at nodal points, is reported. Measured results reveal that there is an optimal range of anchor designs that provide high quality factor (Q) above one million, along with low motional resistance, R_m. Two-anchor- only support design is able to achieve very high Q_s but results in higher motional resistance. Lower structural thickness generally reduces the quality factor Q and R_m owing to interference from out-of- plane modes.     

缩短微机械圆盘谐振器缝隙的电极移动法

针对现有微机械(Micromechanical,也称MEMS)圆盘谐振器串联动态电阻过大的问题,该文提出了电极移动法,将其它MEMS器件的可调性能引入MEMS圆盘谐振器,在现有最窄缝隙工艺条件下实现了电极-圆盘缝隙的进一步缩减,降低了串联动态电阻。该文给出了悬置电极的设计方法,推导了电极移动后有效缝隙宽度的表达式,提出了可防电极接触短路的微小圆孔状凹陷设计,并给出了加入凹陷后的有效缝隙宽度表达式。通过ANSYS仿真结果可知,分别加载2.10 V和66.38 V偏置电压后,0.1 m和1 m电极-圆盘缝隙缩小为0.0016 m和0.01 m。对于0.1~1.1 m缝隙谐振器,串联动态电阻变为原来的10-8倍以下。     

Large Square Resonator Laser With Quasi-Single-Mode Operation

A large square resonator with a size of 8.3 $mu$m can support many resonant modes, including whispering gallery modes. The inclusion of trenches at judicious node positions of a selected mode will not significantly affect this mode (i.e., its quality factor will not be significantly reduced) while the remaining modes will drastically lose power through radiation. Since most of the modes will not be able to overcome their radiation losses, only a single mode will resonate in the modified structure. We demonstrate, experimentally, single-mode operation of this device at a temperature of 4.2 K.      

Monolithic CMOS MEMS Oscillator Circuit for Sensing in the Attogram Range

This letter presents the design, fabrication, and demonstration of a CMOS/microelectromechanical system (MEMS) electrostatically self-excited resonator based on a submicrometer-scale cantilever with ~1 ag/Hz mass sensitivity. The mechanical resonator is the frequency-determining element of an oscillator circuit monolithically integrated and implemented in a commercial 0.35 mum CMOS process. The oscillator is based on a Pierce topology adapted for the MEMS resonator that presents a mechanical resonance frequency of ~6 MHz, a relative low quality factor of 100, and a large motional resistance of ~25 M. The MEMS oscillator has a frequency stability of ~1.6 Hz resulting in a mass resolution of ~1 ag (1 ag = 10^-18 g in air conditions.     

一种利用环形双模谐振器实现的带阻滤波器

提出了一种利用双模环形谐振器实现的带阻滤波器。该滤波器由一个对称的双模环形谐振器以及一段四分之一波长的平行耦合线组成。借助于在普通环形谐振器的两个相对边上添加一对小贴片,环形谐振器的两个简并谐振模式可以被可控的分离,从而可以构成带阻滤波器的工作频带。平行耦合线的作用是为了对双模谐振器进行馈电,同时也被用做两端口间的阻抗变换器。在理论分析之后,利用平面PCB工艺设计制作了滤波器样品,并对其进行了测量,进一步证明这种设计的有效性。     

Comparison of Mode Quality Factors for Equilateral Triangular,Square and Rhombus Optical Micro-Resonators

采用时域有限差分和Padé近似计算了等边三角形、正方形和平行四边形微谐振腔的模式频率和品质因子．数值结果表明等边三角形谐振腔中的谐振模式具有较高的品质因子,这主要是由于等边三角形谐振腔中的模式在横向上得到了完全的限制,而在其它两种谐振腔中,模式在横向上只是得到部分限制．对于边长为4μm,折射率为3.2的等边三角形谐振腔,发现在1.55μm波长处的模式品质因子可达5.5×103．     

Micromechanical resonator with ultra-high quality factor

A 6.3 MHz Lame-mode square resonator with fully differential drive and sense electronics, exhibiting quality factor (Q) values over 1 million in ambient pressures as high as 200 Pa is reported. A maximum Q value of 1.6 million was experimentally measured for the resonator designed for this study. It was also experimentally observed that the Q value for the designed bulk mode resonator was relatively independent for pressures below 200 Pa, suggesting that the Q is pressure limited for pressure higher than 200 Pa.     

高斯反射率方形平凹腔激光模场的有限元分析

利用柯林斯公式和边界有限元方法，将方形球面镜腔的衍射积分方程转化为矩阵方程，并对高斯反射率方形平凹腔的模场分布进行了数值计算。研究结果表明，高斯反射率方形平凹腔具有较好的选模性能，可以应用于高功率激光器以获得高质量的激光光束。     

Dual-mode helical resonators

High performance and compact size are the most important criteria in filter-based products for satellite communication systems. Succeeding the superconducting and dielectric resonators, the conventional single-mode helical resonator ranks favorably on its high unloaded-Q per volume. Improvement of the performance has been demonstrated by operating the helical resonator at a higher order (n>0) mode. In addition, these resonators can also be fabricated onto a high dielectric-constant material to further reduce the size of the filter structure. Detailed design considerations of the dual-mode wire-wound helical resonator filter, as well as implementation of the dual-mode dielectrically loaded helical resonator filter structure, are presented in this paper     

薄膜电阻对微带均衡器的影响研究

为了使微带均衡器满足衰减特性与给定的误差曲线逐点拟和的要求,就必须使其频率可调、衰减可调、品质因数可调。因此,本文通过大量仿真和实验,研究了加载了薄膜电阻的微带谐振器及其在微带均衡器中的应用,研究分析了薄膜电阻对微带均衡器传输特性及驻波特性的影响。研究结果表明将薄膜电阻加载到微带谐振器上构造微带均衡器,可以通过改变谐振器的尺寸使其频率可调,通过改变电阻阻值及位置使其衰减可调、品质因数可调。大量HFSS仿真及实验证明这种方式很适合微带均衡器的设计制造。本文利用这种结构设计制作出了一个宽带微带均衡器,得到了很好的实验结果。     

Miniaturisation and high quality factor of spiral meander spurline resonator for microwave oscillator

The spiral meander spurline structure is an optimal solution for a reduced resonator size and a high Quality factor (Q-factor) compared to other conventional spurline structures. The spiral meander spurline resonator shows not only 38% reduced dimensional effect, but also 16% improved Q-factor compared with conventional meander spurline resonator. Moreover, in order to get more high quality factor, we analysed spurline slot width variation and designed the symmetric dual spiral meander structure, which has a 46.87% improved Q-factor compare with a single spiral meander. The symmetric dual spiral meander structure resonator performance results are shown in a return loss of ?0.76?dB, an insertion loss of ?46.32?dB, and a quality factor of 235 at 6.4?GHz C-band application. In addition, according to the design and performance of the resonator, we can derive from this performance a low phase noise oscillator. The oscillators using symmetric dual spiral meander structure resonator shows good phase noise performances of ?104.43?dBc/Hz at a 100?kHz offset from the carrier frequencies of 6.38?GHz at output powers of 12.2?dBm, respectively.     

300 MHz氮化铝轮廓模式谐振器的设计

氮化铝轮廓模式谐振器(CMR)能够满足现代无线通信对单片、多频段、可重构的多频率源的需求,具有很大的应用前景。针对目前无具体单个CMR频点的设计方法,提出了一种结合CMR性能参数的影响因素分析和有限元计算的CMR设计方法。该文对CMR的谐振频率、质量因子、机电耦合系数和动态电阻等谐振器主要性能参数的影响因素进行理论分析得到CMR结构的初始尺寸,再利用COMSOL有限元软件建立CMR几何模型并进行频域求解得到相应的频率-导纳曲线和频率-质量因子曲线;根据仿真结果和理论计算对CMR初始结构尺寸进行优化,并仿真设计了一个氮化铝CMR,其谐振频率为300 MHz,质量因子约为1 010,机电耦合系数约为1.64%。     

Design of a novel MEMS resonator based neuromorphic oscillator

A novel MEMS based neuromorphic oscillator is presented. Due to compatibility with CMOS process, on-chip integration of electro-statically actuated microresonators is possible with very small size. Also, taking advantage of sacrificial sidewall spacer technique for fabrication of 100 nm vertical gap, as low actuation voltages as 0.5 V is enough for such resonators. Oscillatory neuron dynamics are also studied and design of the resonator and its characteristics are described as a neuromorphic oscillator. There are several practical barriers associated with MEMS implementation of neuromorphic oscillators such as existence of near-to-main mode spurious modes, requiring of UHF high gain trans-impedance amplifier because of very high motional resistance of such resonators, and automatic amplitude control circuit which all investigated in the paper and surmounted as well. A coupling technique for weak connection of such resonators is also described in the paper which allows mechanical low velocity connection of UHF contour mode disk resonators for the first time.     

One and two port piezoelectric higher order contour-mode MEMS resonators for mechanical signal processing

This paper reports on the design, fabrication and testing of novel one and two port piezoelectric higher order contour-mode MEMS resonators that can be employed in RF wireless communications as frequency reference elements or arranged in arrays to form banks of multi-frequency filters. The paper offers a comparison of one and two port resonant devices exhibiting frequencies approximately ranging from 200 to 800 MHz, quality factor of few thousands (1000–2500) and motional resistances ranging from 25 to 1000 Ω. Fundamental advantages and limitations of each solution are discussed. The reported experimental results focus on the response of a higher order one port resonator under different environmental conditions and a new class of two port contour resonators for narrow band filtering applications. Furthermore, an overview of novel frequency synthesis schemes that can be enabled by these contour-mode resonators is briefly presented.     

电阻加载的螺旋形谐振器在微带均衡器中的应用

本文给出了一种薄膜电阻加载的矩形螺旋形谐振器,并利用其设计了一种甚小尺寸的微带均衡器子结构电路,对薄膜电阻的加载位置也进行了研究.通过在螺旋形谐振器中引入电阻加载,使得该电路能够进行品质因数调节.分析表明这种电阻加载的螺旋形谐振器不仅能够进行中心频率调节、曲线衰减幅度调节,而且能够对谐振回路的品质因数进行调节,适合在微带均衡器中应用,为微带均衡器的设计提供了一种新的设计途径.     

电阻加载的螺旋型谐振器在微带均衡器中的应用

提出了一种薄膜电阻加载的矩形螺旋型谐振器,并利用其设计了一种甚小尺寸的微带均衡器子结构电路,对薄膜电阻的加载位置也进行了研究.通过在螺旋型谐振器中引入电阻加载,使得该电路能够进行品质因数调节.利用高频结构仿真软件分析表明这种电阻加载的螺旋型谐振器不仅能够进行中心频率调节、曲线衰减幅度调节,而且能够对谐振回路的品质因数进行调节,适合在微带均衡器中应用,为微带均衡器的设计提供了一种新的设计途径.     

Investigating Transient Thermal Effects in Flash-Lamp-Pumped Heat Capacity Nd:YAG Rod Laser

Transient thermal effects induced in the laser medium under heat capacity (HC) mode of operation and its influence on the output laser performance is presented. Thermal loading and the resulting negative lensing effects are shown to be different under lasing and nonlasing conditions. Negative refractive power of laser rod affecting the laser resonator stability was observed to be the major cause for the decline in the output power in HC mode. An active resonator model based on measured thermal refractive power is discussed and impact of resonator design parameters on laser beam quality is investigated. An output power of 152 W in HC mode for a run time of 5 s has been obtained. Comparative performance results in conventional continuously cooled (CC) mode is also discussed to highlight the characteristic differences in the two operating modes. Nearly 2–3 times better output beam quality was obtained in HC mode as compared to CC mode.      

A Single-Crystal-Silicon Bulk-Acoustic-Mode Microresonator Oscillator

A timing reference incorporating a single-crystal-silicon micromechanical resonator with a quality factor of larger than one million and a resonant frequency of 2.18 MHz is demonstrated. The resonator is excited in the square extensional bulk acoustic mode at 4 mtorr, and it has been fabricated in a foundry SOI MEMS process. The silicon microresonator is adapted as a timing element for a precision oscillator with a measured short-term Allan deviation of 0.6 ppb.      

基于工程应用的半球谐振陀螺结构设计研究

半球谐振陀螺仪(HRG)是极具发展前景的新型固态波陀螺仪,其发展的关键是如何设计制造出精致可靠的陀螺结构部件.该文以工程应用中成熟半球陀螺半径尺寸为例,对谐振子部件几何尺寸中壁厚和轴柄半径的设计从抗模态干扰方面提出优化建议,并首次将抗冲击过载能力纳入优化设计考量因素中,通过COMSOL软件仿真得出壁厚和轴柄半径取值范围...     

高阶耦合模倒圆锥双重正弦同轴结构频率响应

为了形成带宽窄、品质因数Q高、选择性好的同轴布喇格反射器,提出一种倒圆锥型双重正弦同轴结构设计。基于耦合模式理论,在普通正弦槽结构的基础上,叠加刻蚀周期较小的辅助正弦分布,在导体内外壁上增加倒锥度,形成倒圆锥型双重正弦同轴布喇格结构。通过FORTRAN软件仿真得出,与普通正弦槽相比,倒圆锥型双重正弦同轴布喇格结构的工作模式和竞争模式的带宽更窄,品质因数Q得到提高,残余旁瓣现象得到抑制。同时,竞争模式的中心谐振频率点远离工作模式,带隙重叠进一步分离,频率选择性得到提高。该结构设计简单,方法合理,可以更好地分离工作模式和竞争模式,构建高品质因数Q、高功率的单一高次模谐振腔。