A batch-fabricated silicon accelerometer

An extremely small batch-fabricatable accelerometer has been developed using silicon IC technology. The device, 3 mm long and weighing 0.02 g, is a simple cantilevered beam and mass structure sealed into a silicon and glass package. The fabrication of the accelerometer is described, and the theory behind its operation developed. Experimental results on sensitivity, frequency response, and linearity are presented and found to agree with theory. The accelerometer is capable of measuring accelerations from 0.001 to 50 g over a 100-Hz bandwidth, while readily implemented geometry changes allow these performance characteristics to be varied over a wide range to meet the needs of differing applications.     

A method for designing broad-band microstrip antennas inmultilayered planar structures

The narrow bandwidth of a microstrip antenna is one of the important features that restrict its wide usage. A simple and practical method for the design of broad-band microstrip antennas is presented in this paper. Utilizing this design technique, several two-layer microstrip antennas have been proposed. To confirm the applicability of the method for the designs of antennas at L-band, experiments have been carried out. The measured results show that the proposed antennas have a bandwidth of up to 25.7%. Also, the method proposed in this paper is applicable to the design of other types of multilayered planar antennas     

基于强度解调的低成本光纤悬臂式加速度计

该文研究了一种基于强度解调的低成本光纤悬臂式加速度计。该加速度计由接收光纤、发射光纤、陶瓷插芯和陶瓷套管组成,接收光纤和发射光纤均为单模光纤(SMF)。对该加速度计的灵敏度进行理论分析并制作了一个光学加速度计,搭建了实验系统。实验结果表明,在工作频带30~1 000 Hz,该加速度计具有71.5 mV/g(g=9.8 m/s²)的灵敏度和良好的相频特性。     

Compact planar microstrip-slotline symmetrical ring eight-portcomparator circuits

It is shown that the common eight-port comparator circuit may be constructed starting from a fully symmetrical eight-port device. The conditions for a lossless symmetrical eight-port circuit to be a symmetrical eight-port comparator are derived. These are used to design several versions of a planar ring microstrip-slotline comparator. Two experimental versions of such an eight-port circuit have been constructed using a planar microstrip-slotline technique. In the case of the second version, the ring circumference is only a wavelength at midband. This is the same circumference as the common 180° magic T ring circuit, four of which are frequently used to build a conventional comparator. The bandwidth of these eight-port planar ring circuits can be as much as 30% for a return loss better than 20 dB. A quasi-optic eight-port symmetrical comparator circuit based on a single wire grid is discussed. It has no bandwidth limitation     

A high performance Σ-Δ readout circuitry for μg resolution microaccelerometers

This paper reports a second order electromechanical sigma-delta readout for micro-g resolution accelerometers in addition to other high-sensitivity capacitive microsensors with large base capacitance. The chip implements a switched-capacitor readout front-end and an oversampled sigma-delta modulator, and hence can be used for both open-loop analog readout and closed-loop control and readout with direct digital output. The readout circuit has more than 115 dB dynamic range and can resolve less than 3 aF/√Hz. Also this IC includes start-up circuit and feedback mechanism for closed-loop control of the accelerometer with a single 5 V supply in a ±4 g range. Together with the accelerometer, bandwidth of the overall system is limited with the sensor resonance frequency (1.53 kHz) in the open-loop mode. However in closed loop mode, oversampling of the acceleration data increases the bandwidth of the system up to few hundred kilohertz which is limited with the cut-off frequency of the low-pass filter placed at the output of the system. The start-up circuit allows rebalancing of a thick silicon proof mass with the limited 5 V supply after system start from power down or in the case of over-range input acceleration. The readout chip has been combined with a Silicon-On-Glass lateral accelerometer, which has a high sensitivity of 1.88 pF/g with large proof mass and long finger structures. A digital filtration and decimation circuitry is also implemented to signal process the output bit stream of the readout circuit. The complete module consumes 16 mW from a ±2.5 V supply and has an adjustable sensitivity up to 8 V/g with a noise level of 4.8 μg/√Hz in open-loop.     

一种新型多周期平面电磁带隙结构

根据不同周期平面电磁带隙(EBG)结构所具有的不同带隙特性以及平面EBG结构的等效电路,提出一种新型多周期平面EBG结构。通过Ansoft HFSS软件对该EBG结构的电磁带隙特性进行仿真验证。结果表明:所提出的EBG结构抑制深度为-30dB时,阻带范围为0.7~8.4GHz,阻带宽度为7.7GHz.相对于传统大周期和小周期平面EBG结构,其阻带宽度分别增加2.1GHz和1.2GHz.仿真结果也表明新型EBG结构可以有效抑制同步开关噪声(SSN),并为展宽平面EBG结构的禁带带宽提供一种新方法。最后,通过时域仿真验证新结构具有较好的信号完整性。     

Estimated acceleration feedback applied to a telescope servo system

Methods of increasing the bandwidth of a telescope servo system have been investigated. The results of this research, both via simulation and practical evaluation, have shown that the application of acceleration feedback can increase the position servo loop bandwidth by a factor of 4. Acceleration feedback has been applied successfully to the servo system of a real machine. This has been achieved both by the use of accelerometers and by software-based acceleration calculation and state estimation techniques. The performance of the software-based techniques matches that of the accelerometer if the sampling rate of the servo system is high enough.     

基于多开口谐振环的双频左手材料设计

基于多开口谐振环结构,提出一种双频宽带左手材料.结构由正方形谐振环与工字型负载线组合而成,具有频带宽、频率可调与易于加工的特点.通过软件仿真与样品测试提取等效介质参数,结果表明该结构左手频带分别位于7.8~8.2 GHz和8.4~13.4 GHz,左手带宽共计5.4 GHz.相较于传统结构,该结构带宽更宽且在一定范围可对左手频带进行调节.     

基于MEMS传感器组合的行人室内高度定位算法

针对气压计易受环境温度影响的问题,该文提出了一种基于微机电系统(MEMS)加速度计和气压计融合的行人室内高度定位算法。该算法分别利用x轴加速度计的峰值特征和z轴加速度计的四分位距特征进行上、下楼判定;然后利用滤除掉气压突跳点的气压计数据进行高度解算;最后行人平走时,将解算高度修正到半层楼高的整数倍,减少高度误差。实验结果表明,该文提出的行人室内高度定位算法不易受环境温度的影响,解算高度与实际楼层高度的误差小于2 m,可将人员定位到正确楼层。     

Printed Planar Antenna for Wideband Applications

A compact planar antenna operating at a frequency range of 3–16 GHz is presented for wideband applications. The antenna is composed of a square patch fed by a microstrip line and a partial ground plane with a rectangular slot. The proposed antenna is very easy to be integrated with microwave circuitry for low manufacturing cost. The flat antenna has a compact structure and the total size is 29 mm × 22 mm. The result shows that the measured impedance bandwidth (VSWR≤ 2) of the proposed antenna is 3.2–15.44 GHz, with a notch from 4.7 to 5.8 GHz. The effects of the structure parameters on impedance bandwidth are also investigated. Details of the proposed compact planar antenna design are presented and discussed.     

Ultra Wide Band (UWB) Horseshoe Antenna for Future Cognitive Radio Applications

In this paper, an UWB micro-strip antenna design has been proposed which is suitable for future cognitive radio applications. The geometry of proposed antenna is composed of two semi-circles with their interior modified in order to achieve higher impedance bandwidth. The semi-etched ground provides further bandwidth enhancement. The proposed antenna is fabricated on an inexpensive dielectric substrate FR-4 with relative permittivity of 4.4 and thickness of 1.6 mm. The overall dimensions of UWB antenna are 60?×?60?×?1.6 mm and have a bandwidth of 5.7 GHz. The designed antenna covers the most commonly used wireless communication bands such as DCS-1800, ISM bands, GPS, Wi-MAX, WLAN, 3G, 4G, etc. The design process and the variations in antenna’s performance due to different parameters has been discussed. The design and simulation of the antenna are carried out in the Ansys Electronic Desktop HFSS. The measured results are in good agreement with simulated results and design theory which shows that the proposed antenna is good candidate for the UWB applications.

     

三分量全保偏光纤加速度传感器的研究

报道了三分量全保偏光纤加速度传感器的实验研究结果。传感器由6个弹性柱体共同支撑1个质量块构成三分量结构,由3个迈克尔逊全保偏光纤干涉仪共用一个光源组成。光学部分采用全保偏光纤干涉仪结构,消除了干涉光束偏振态随机变化引起的信号衰落,采用光频调制相位载波解调信号处理技术,消除了相位随机漂移引起的信号衰落,从而实现了对加速度信号的稳定检测。传感器的工作频带为5~500 Hz,加速度灵敏度达到660 rad/g,系统最小可测相位差为10-5rad,最小可测加速度达1.5×10-7m/s2,工作频带内加速度灵敏度变化小于2 dB。三轴加速度灵敏度和频率响应曲线与理论分析的结果基本一致。     

一种基于新型双轴圆弧铰链的二维FBG加速度传感器

为了实现大跨度桥梁中拉索构件的二维(two-dimensional, 2D)振动信号高精度测量,本文设计并研究了一种小型化的新型2D光纤布拉格光栅(fiber Bragg grating, FBG)加速度传感器,以解决现有FBG加速度传感器体积与质量较大的问题。所设计的FBG加速度传感器主要由含有质量块的双轴圆弧铰链、4个固定支架,以及刻有4段阵列FBG的光纤组成。通过建立FBG加速度传感器的动力学普遍方程,得到灵敏度与固有频率的理论数值,另外辅以Abaqus软件对其进行有限元仿真以验证理论推导的结果。实验测试数据表明,FBG加速度传感器的固有频率约为500 Hz,双FBG的布置使其灵敏度可以达到595.2 pm/g,此外对称推挽的圆弧铰链设计还具有优异的横向抗干扰和温度自补偿性能。最后以某中承式钢管混凝土拱桥为实际工程案例,使用所设计的2D FBG加速度传感器实现了吊索索力的有效测量。     

A novel optical accelerometer

A novel accelerometer based on a PIN photo-detector and a micro-machined cantilever-beam-supported optical shutter with seismic mass has been designed, fabricated, and tested. Anisotropic wet etching of 〈110〉 orientation silicon in KOH is used to fabricate an optical shutter consisting of evenly spaced vertically etched slots. The shutter, which also constitutes the seismic mass of the accelerometer, is suspended by two cantilever beams. The special structure of the device and the high aspect ratio of the cantilever beams (7.5) permit freedom of the movement for the proof mass (the shutter) on the ±X axis only. The actual size of the device is 3×4 mm and its amplified output varies linearly from -3.6 V to +3.6 V for accelerations from -84 g to +84 g. The measured resonant frequency of the device is 3.2 KHz. A dual diode structure is chosen for the photo-detector to compensate for temperature drift and the amplified output voltage changes by less than 40 mV for a temperature variation from 25°C to 50°C     

一种适用于高速电路中SSN抑制的紧凑型电磁带隙新结构

该文根据电磁带隙(EBG)结构的带隙形成机理以及共面EBG结构的等效电路,提出了一种适用于高速电路中同步开关噪声(SSN)抑制的紧凑型EBG结构,使用Ansoft HFSS对该结构进行仿真分析。仿真结果表明在抑制深度为-30 dB时,阻带范围为0.6-6.4 GHz,阻带带宽为5.8 GHz,与传统的L-bridge结构相比,阻带带宽增加了1.8 GHz,相对带宽增加了45%,实现了较低的带隙中心频率以及较宽的阻带带宽,并用Ansoft Designer通过时域仿真验证该结构具有较好的信号完整性。     

Extension of measurement bandwidth in an AMB-based gyroscopic sensor

A gyroscopic sensor using active magnetic bearing (AMB) is studied both theoretically and experimentally. The sensor has been proposed to realize high accuracy, compact and low-cost sensors, and it utilizes the control function of the AMB. The sensor works as a two-axis gyroscopic sensor and also as a three-axis servo-type accelerometer. Angular velocities and accelerations are measured based on the control signals for cancelling the inertial effects that act on the AMB rotor. The methods to detect the accelerations and angular velocities have been validated from several experimental results. In addition, it has been indicated that there is an upper limit in the measurement bandwidth of the sensor when the two-axis angular velocity is measured simultaneously. However, factors determining the limit have not been presented in a concrete manner. This paper discusses these factors and presents a methodology that can extend the measurement bandwidth of the sensor. The limiting factors are investigated extensively by analysis, numerical simulations and experiments with the AMB. The relationship between the measurement bandwidth and the control system is also investigated. In addition, the measurement range of the gyro is discussed.     

A Compact Zeroth‐Order Resonant Antenna on Vialess CPW Single Layer

In this letter, a novel zeroth‐order resonant (ZOR) antenna on vialess co‐planar waveguide (CPW) is proposed. It is based on a composite right/left‐handed CPW transmission line. To achieve a compact size, this antenna utilizes the ZOR condition, and its reactive parameters determine the resonant frequency. Each unit cell is composed of a metallic top patch and meander lines. Since it is realized on the CPW single layer, the proposed antenna has the benefits of being a compact size and easy to fabricate. The bandwidth of 6.8% and efficiency of 62% are experimentally achieved. Its bandwidth is enhanced compared with other ZOR antennas.     

Broadband circularly polarised planar array composed of a pair of dielectric resonator antennas

A new type of planar array composed of a pair of dielectric resonator antennas has been devised and tested. Both the radiation patterns and ellipticity properties are presented. The 2 dB ellipticity bandwidth obtained was approximately 15% at X-band.     

数字闭环加速度计带宽测试方法的研究

为了消除传统电模拟法引入的激励信号对力矩器驱动模块造成的影响,提出了一种在数字闭环加速度计系统反馈回路数模转换器输入端叠加一个激励信号来测试系统带宽的方法.通过对该方法的电激励模型进行分析,表明在带宽测试时系统反馈回路D/A输入端叠加激励信号可以等效为外界输入的加速度.搭建测试平台测试系统带宽,实验表明,用该方法测得的数字闭环加速度计系统带宽与传统机械振动法的测试结果相接近.该方法未增加其它电路,降低了系统的复杂度,消除了电模拟法外加激励信号源对力矩器驱动模块的影响.此外,该方法操作快速简单、便于在线测试,可满足大多数数字闭环加速度计的带宽测试要求.     

叠加电桥检测的加速度传感器的设计

This paper describes the design,simulation,processing and test result of a high sensitivity accelerometer based on the piezoresistive effect which uses an overlay bridge detection method.The structure of this accelerometer is supersymmetric "mass-beams".This accelerometer has 8 beams,where two varistors are put in the two ends.Four varistors compose a Wheatstone bridge and the output voltages of the 4 Wheatstone bridges have been superimposed as the final output voltage.The sensitivity of the accelerometer can be improved effectively by these clever methods. A simplified mathematical model has been created to analyze the mechanical properties of the sensor,then the finite element modeling and simulation have been used to verify the feasibility of the accelerometer.The results show that the sensitivity of the accelerometer is 1.1381 m V/g,which is about four times larger than that of the single bridge accelerometers and series bridge sensor.The bandwidth is 0-1000 Hz which is equal to that of the single bridge accelerometers and the series bridge sensor.The comparison reveals that the new overlay detection bridge method can improve the sensitivity of the sensor in the same bandwidth.Meanwhile,this method provides an effective method to improve the sensitivity of piezoresistive sensors.