Key Engineering Materials Vols. 609-610

Abstract: In this work, piezoresistive stress sensors test circuit fabricated into the sensitive structure as part of the normal processing procedure is used to measure the stresses difference distribution before and after the assembly. Sensor resistances were recorded before and after the adhesive bonding. Using the theoretical equations, the stresses on the die surface have been calculated from the data of sensor resistances. This technology not only provides a performance diagnostic tool for the sensitive structures and the miniature components, but also presents a design tool for low-stress micro-assemblies of miniature components.

Abstract: In checking to see the performance of the nanometer accuracy capacitive sensor, some parameters, such as, the linearity, repeatability and so on are presented as the characterization parameters. Firstly, the series of test method and test devices is designed to measure and evaluate these parameters of a capacitance sensor. Secondly, the measuring setup is consisted by the traceable laser interferometer with high accuracy and nanometer micro-motion system. Finally, in order to meet the displacement linearity test, the measuring method is in line with the Abbe principle. Experimental results indicate that this approach and setup can realize in the best reference line to the minimum linearity is better than 0.01%, repeatability is better than that of 3.5nm, resolution is less than 0.3nm, measurement capability is more unwavering than 3nm. It can satisfy the measurement requirements of capacitance sensor performance testing with nanometer accuracy.

Abstract: Gyroscope is a sensor thatmeasure angular velocity which is widely used in various fields [1]. The analogprocessing technology of Gyro-signal is very mature, but due to the noise andother shortcomings of the analog circuit, the development of micro-mechanical gyroscopeis limited. Digital gyroscope has superior performance and accuracy, so thesignal processing of gyroscope will take digital methods [2]. This paper designsa platform for the digital signal processing of Silicon gyroscope. By using FPGAextend A / D and D / A interface method implement the signals from outside inputto output, build a digital signal processing platform of the minimum system,then design the overall digital signal of the hardware part and the controlsection of the software part, synthesis the designed platform which doesn’tdepend on crafts use the Xilinx Synthesis tool and gave the synthesizedresults, verify the correctness of the design eventually.

Abstract: Linearity, dynamic linearity particularly, is an important parameter in measuring the performance of an accelerometer. The Hopkinson bar has been widely used in calibration of high g accelerometer and other high overloading conditions. Based on one-dimension stress wave theory and superposition theory of elastic waves, designed a Dual Warhead Hopkinson bar to demarcate the dynamic linear parameters of high g micro accelerometer accurately. A finite element model for Hopkinson bar calibration system was created, ANSYS/LS-DYNA was employed to simulate the operation process of Hopkinson bar, and the effects of the projectile's materials, adjustment pads materials and thickness on the acceleration waveform were found.

Abstract: A ring resonator based on Silicon-on-Insulator (SOI) planar optical waveguide for micro biochemical sensor application is designed and simulated in this paper. The SOI optical waveguide is made with a ridge structure. According to the optical waveguide mode theory and the performance of the ring resonator, the size of the single mode ridge waveguide and the structure of the ring resonator are obtained. Based on the structure principle and the transmission mechanism of electric field of the ring resonator, the power transfer function and the parametric equation of sensitivity are derived. As a result, the value of Q of the ring resonator can reach 10³ magnitudes. At last, the structure and the transmission mechanism of electric field in the ring resonator are simulated in MATLAB software.

Abstract: In this paper, we report a MEMSbased electrostatic field sensor (EFS) using out-of-plane thermal actuation. The EFS mainly consists of shuttles, sensing electrodes, and clamp-clamp beams. The clamp-clamp beam with a hump is treated as thermal actuator to drive the shuttle, which is to modulate the external electrostatic field. The EFS was fabricated by a standard surface micromachining process and the area of the EFS is less than 2.5mm×2.5mm. The EFS has been tested and achieved a resolution of 60V/m.

Abstract: As a new type of underwater acoustic sensors,the principle of the MEMS hydrophone is introduced in this paper.MUSIC is a algorithm for estimating the parameter of the signal and it has a high resolution.In order to verify DOA estimation performance of MEMS vector array,experiment has been done.the experiments results showed that the MEMS vector array can achieve DOA estimation and track the underwater moving target.thus,it is concluded the feasibility of the MEMS vector array.

Abstract: Road surface sensors system, which monitors the road conditions and raises an alarm when necessary, plays a very important role in the safety of transportation. The temperature detection sensor is used to measure the temperature on and beneath the road surface. It synthetically estimates the road conditions in cooperation with other sensors, such as water film sensor, salinity sensor and so on. In this paper, the theory, circuit structure and testing method of the temperature detection sensor have been introduced, and the data processing pattern and accuracy of results have been improved.

Abstract: Road surface sensors system, plays a very important role in the highway traffic field. Comprehensive estimation of road condition, will distinctly enhance the safety of transportation. Road condition sensor is used to distinguish the coverings on road surface, such as water, snow, ice, frost and so on. In this paper, we introduce the multiple frequency detecting technology used in the road surface sensors system, and design the road condition sensor to detect coverings on road surface. The main work includes design, measurement and improvement of the sensor.

Abstract: A transistor-level circuit design of charge pump is introduced to drive the inertial device. The design is made of several big modules, including main charge pump module, band gap reference module, comparator module, oscillating module, control module, temperature protection module. A three-stage charge pump is applied to achieve 5 V to 18 V DC/DC conversion, and each stage uses the cross coupled charge pump circuit, taking body effect, threshold voltage drop and efficiency into account. Considering efficiency and power consumption, the band gap reference module adopts a self-biased op amp. To make the comparator transient response fast, the op amp cascades two inverters. The temperature protection module sets a maximum temperature to protect the charge pump. The control module is composed of a data selector, a two-phase non-overlap clock circuit and a frequency divider to optimize clock signal. Then simulations are given and the charge pump is analyzed, finally the efficiency of charge pump is calculated. Designed in CSMC 0.5um process, the charge pump has an efficiency of 87.63 percent, a 19.85V output voltage, a 100 mA output current, and 6.05mV ripple.