Abstract: According to researching the spin traveling wave pump, the relationship of the characteristics of magnetic fluid and the press is investigated under the spin magnetic field by the theory method. The relationship of moving, magnetic field and press is investigated by the decoupled computation between the magnetic field and force. The method is scientificity and rationality by the testing. The distributing shape of magnetic fluid in the pump is affected by the adding magnetic field under the spin magnetic field when the magnetic fluid is filled in the pump. At the same time, the adding magnetic field is affected by magnetic particles of magnetic fluid. The magnetic fluid can be moved by the effect of the adding magnetic field in the pump. The flux of magnetic fluid increases with the magnetic field.
Abstract: pressure sensor, CrSi resistor networks, temperature compensation. Abstract. In this paper, focused on especial requirement monolithic integrated resistance pressure sensor, pressure structure, signal processing circuits and process compatible technology of sensor and IC were studied. The feebleness pressure signal monitoring circuits was designed, high precision CrSi resistor networks was used for temperature compensation of resistance pressure sensor, and a monolithic integrated pressure sensor only 2.3×2.3mm2 was obtained. The measuring results are as follows, measurement range is 5-115kPa, the maximum Vout is more than 4.5V, sensitivity is 1.2%.
Abstract: The reference is an important part of the micro-gyroscope system. The precision and stability of the reference directly affect the precision of the micro-gyroscope. Unlike the traditional bandgap reference circuit, a circuit using a temperature-dependent resistor ratio generated by a highly-resistive poly resistor and a diffusion resistor in CMOS technology is proposed in this paper. The complexity of the circuit is greatly reduced. Implemented with the standard 0.5μm CMOS technology and 9V power supply voltage, in the range of -40~120°C, the temperature coefficient of the proposed bandgap voltage reference can achieve to about 1.6 ppm/°C. The PSRR of the circuit is -107dB.
Abstract: Parallel-plate capacitor whose plates both fixed to elastic supports is presented and analyzed in this paper, and its cantilevers model is analyzed to study the parameter dependence of pull-in voltage. The whole process of voltage calculation is based on material mechanics theories and analytical methods, and the results are verified by simulation of MEMS software, which is mainly aiming at the effects of plate dimensions on pull-in voltage. It is concluded that the longer are the supporting beams, the smaller are the effects of plate’s parameters on voltage, besides, the effect extent of longitudinal length of plate is little larger than that of transverse length.
Abstract: A two-dimensional MEMS resonant mirror is presented in this paper, which is capable of scanning a laser beam two-dimensionally in the both vibration modes. Based on the MEMS resonant mirror, a simulation method is presented to study the two-dimensional scanning characteristics. The scanning time of a frame is obtained and the impacts on the scanning time of a frame by the scanning parameters are simulated and analyzed. The simulation results have a great significance for the two-dimensional MEMS resonant mirror in space applications.
Abstract: The MEMS A0 mode Lamb wave (flexural plate wave) ultrasonic devices have been shown to be extremely useful for sensor and actuator applications. The design and fabrication process of a MEMS flexural plate wave device based on the LTO/ZnO/LTO/Si3N4 multilayered composite membrane are presented. The flexural plate wave was respectively launched and received by both Al interdigital transducers. In order to reduce the stress of the thin membrane induced mainly by the in-plane compressive stress of ZnO film, two fabrication process of DC and RF magnetron sputtering were used to deposit the ZnO films, respectively. The FPW device based on LTO(0.2μm)/ZnO(1μm)/ LTO(2μm)/Si3N4(0.5μm) thin membrane was fabricated. The center frequency of the MEMS flexural plate wave device is measured at 3.69MHz, which agrees with the theoretical predictions.
Abstract: A new isolation optimization method of radio frequency (RF) microelectromechanical systems (MEMS) capacitive switches is carried out in this paper. We simplified the coplanar waveguide and the top movable electrode as two-port network. The existence of the maximum isolation of single switch is proved theoretically based on circuit model and S-parameters model. The isolation of the distributed switches with lossless transfer lines, which is the function of the transfer lines length and the impedance of metal beams, is described by mathematic expressions and simulated in a numerical method. We find that the isolation varies periodically with θ and f, which are the electrical length between metal beams of the distributed switches and the signal frequency. It achieves the maximum value 83dB at θ=π/2 for 2-beams switch. However, different from single beam switches, the distributed switches maximum isolation is near but not precisely at the resonance frequency f0. The bandwidth of RF signal can be widened to about 200% for 5-beams switch by using the proposed design method. The results will be useful for Resistance-Inductance- Capacitance parameters optimization of RF MEMS Capacitive switches.
Abstract: This paper reports on the development and characterization of piezoresistive stress and temperature sensors fabricated on silicon-on-insulator (SOI) wafer. The sensor chip consists of a 5x5 array elements enabling the simultaneous measurement of the absolute temperature as well as in-plane stress components in a temperature compensated manner. Each cell comprises a p-type piezoresistor rosette paralleling to the  crystal direction of silicon, an n-type piezoresistor rosette along the  crystal direction and a temperature sensor. Design, fabrication and characterization of piezoresistive and temperature sensors are described in detail. Moreover, based on the flexible printed circuit board, the prepackaging technique of sensors is reported and the electrical connections between the testing sensors and external measuring devices are achieved, then the changes in resistance versus temperature changes are measured in our experiment, the results show that this approach can be used for the signal measurement of sensor before the second packaging and on-line measurement of packaging stresses.
Abstract: Grating as an important spectral component can be applied to spectral analysis, filtering, dispersion compensation, sensing and so on. Their advantages are compactness, potentially high actuation speed and the ability to deflect light at large angles. In this paper, a MEMS interdigitated-comb grating actuated by a comb-drive actuator is presented. An experiment is performed to demonstrate how the proposed grating works with an applied voltage. At 85V, the displacement of comb-drive actuator can achieve 2.1μm; accordingly the gap between the interdigitated-comb gratings varies by 2.1μm. The mechanical and the optical sensing properties of the MEMS grating are both analyzed in this paper. This grating can be widely used in optical sensor and to detect the micro-displacement.