Xue Chenyang

Package Optimization of the Cilium-Type MEMS Bionic Vector Hydrophone

We optimize the package of the cilium-type MEMS bionic vector hydrophone introduced by Chenyang and Wendong in 2007, which has the disadvantages of a low receiving sensitivity, narrow frequency band, and fluctuating frequency response curve. Initially, a full parametric analysis of frequency response and sensitivity with different material sound transparent cap were made. Then, we propose and realize an umbrella-type packaged structure with high receiving sensitivity and wide frequency band. The theoretical analysis and simulation analysis are conducted by ANSYS software and LMS virtual. Lab acoustic software. Finally, to verify the practicability of the package, the umbrella-type packaged hydrophone calibration was carried out in the National Defense Underwater Acoustics Calibration Laboratory of China. The test results show that the performance of umbrella-type hydrophone has been greatly improved compared with the previous packaged hydrophone: exhibiting a receiving sensitivity of -178 dB (increasing by 20 dB, 0-dB reference 1 V/μPa), the frequency response ranging from 20 Hz to 2 kHz (broaden one times), the fluctuation of frequency response curve within ±2 dB, and a good dipole directivity.

Enhancing the Robustness of the Microcavity Coupling System

A novel method to enhance the robustness of the microcavity coupling system (MCS) is presented by encapsulating and solidifying the MCS with a low refractive index (RI) curable UV polymer. The encapsulating process is illustrated in detail for a typical microsphere with a radius of R about 240μm. Three differences of the resonant characteristics before and after the package are observed and analyzed. The first two differences refer to the enhancement of the coupling strength and the shift of the resonant spectrum to the longer wavelength, which are both mainly because of the microsphere surrounding RI variation. Another difference is the quality factor (Q-factor) which decreases from 7.8×107 to 8.7×106 after the package due to the polymer absorption. Moreover, rotation testing experiments have been carried out to verify the robustness of the package MCS. Experimental results demonstrate that the packaged MCR has much better robust performance than the un-package sample. The enhancement of the robustness greatly promotes the microcavity research from fundamental investigations to application fields.

Pressure effects in AlAs/InxGa1−xAs/GaAs resonant tunnelling diodes for application in micromachined sensors

This paper reports the current?voltage characteristics of [001]-oriented AlAs/InxGa1?xAs/GaAs resonant tunnelling diodes (RTDs) as a function of uniaxial external stress applied parallel to the [110] and the [10] orientations, and the output characteristics of the GaAs pressure sensor based on the pressure effect on the RTDs. Under [110] stress, the resonance peak voltages of the RTDs shift to more positive voltages. For [10] stress, the peaks shift toward more negative voltages. The resonance peak voltage is linearly dependent on the [110] and [10] stresses and the linear sensitivities are up to 0.69?mV/MPa, -0.69?mV/MPa respectively. For the pressure sensor, the linear sensitivity is up to 0.37?mV/kPa.

Wireless contactless pressure measurement of an LC passive pressure sensor with a novel antenna for high-temperature applications

In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600 °C. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor.

Raman scattering studies on PZT thin films for trigonal?tetragonal phase transition

PZT thin films were successfully prepared through sol-gel. The annealing temperature was confirmed through DTA analyzing. The trigonal and tetragonal phase transition was analyzed through Raman scattering. The intensity of the A1(2TO) mode and the A1(3TO)T mode were enhanced with the increase of the annealing temperature. So, the conclusions were obtained that the trigonal phase turned into a tetragonal phase as temperature increased.

Design of a Bionic Cilia MEMS three-dimensional vibration sensor

A biomimetic three-dimensional piezoresistive vibration sensor based on MEMS technology is reported. The mechanical properties of the sensor are analyzed and the static and dynamic characteristics of the sensor are simulated by ANSYS Workbench 12.0. The structure was made by MEMS processes including lithography, ion implantation, PECVD, etching, etc. Finally, the sensor is tested by using a TV5220 sensor auto calibration system. The results show that the lowest sensitivity of the sensor is 394.7 μV/g and can reach up to 460.2 μV/g, and the dimension coupling is less than 0.6152%, and the working frequency range is 0–1000 Hz.

Piezoresistive properties of resonant tunneling diodes

A measurement system was designed and established to test the piezoresistive properties of resonant tunneling diodes (RTDs). The current-voltage characteristic shifts of RTD at different stress states were detected. The experimental results demonstrate that the piezoresistive sensitivity of RTD is larger than 1 × 10−8 Pa−1. To accurately represent the piezoresistive properties of RTD, the current-voltage characteristic coherence of the same RTD was tested. According to the experimental results, the largest relative resistance shift of an RTD in the same measurement environment is less than 3%, of which 1% is caused by the testing apparatuses.

Attitude Determination Based on Location of Astronomical Markers With Skylight Polarization Pattern

Many social insects, such as desert ant and honeybees, are able to utilize the natural skylight polarization information for navigation, which has advantages in immunity to the interference of external environment and thus shows higher stability and accuracy. Inspired by it, we attempt to explore a new bionic method for attitude determination by use of polarization pattern. In practice, we first capture the polarization data and based on it, to figure out the location of the sun through clustering. Then, with respect to the relatively consistent spatio-temporal relation between the sun and the zenith, the location of the zenith is accordingly determined. The coordinate of the zenith is adopted to establish the attitude rotation matrix and by which to work out the vehicles attitude. Finally, we set up a simulation vehicle platform to test the effectiveness of the approach with the theoretical polarization pattern derived from the Rayleigh single-scattering theory and actually detected pattern by the polarization analyzer.

Synthesis of superparamagetic iron oxide nanoparticles in carbon reduction method

The current paper presents our new approach in synthesizing superparamagetic iron oxide nanoparticles. The Fe3O4 nanoparticles (~500nm) are synthesized through carbon reduction method, which is a brand new method. The best parameters of this method are fixed through characterizing transmission electron microscope (TEM), X-Ray Diffraction (XRD) and Vibrating Sample Magnetometer (VSM) of the Fe3O4 nanoparticles synthesized under different experimental conditions. The TEM characterization results show that the best ratio of the carbon and ferric chloride is 3:1 and the most suitable calcining time is 3 hours. The nanoparticles, which were obtained with furnace cooling under vacuum condition after 3 hours calcining, have the best magnetic properties and most stable crystal from. Moreover, the quantitative analysis of this new method is taken to confirm the repeatability of this method. The actual qualities of the Fe3O4 nanoparticles are always consistent with the theoretical one, which indicates that the repeatability of this method is excellent.

High-Q micro-ring resonators and grating couplers for silicon-on-insulator integrated photonic circuits

An ultra-small integrated photonic circuit has been proposed, which incorporates a high-quality-factor passive micro-ring resonator (MR) linked to a vertical grating coupler on a standard silicon-on-insulator (SOI) substrate. The experimental results demonstrate that the MR propagation loss is 0.532 dB/cm with a 10 μm radius ring resonator, the intrinsic quality factor is as high as 202.000, the waveguide grating wavelength response curve is a 1 dB bandwidth of 40 nm at 1540 nm telecommunication wavelengths, and the measured fiber-to-fiber coupling loss is 10 dB. Furthermore, the resonator wavelength temperature dependence of the 450 nm wide micro-ring resonator is 54.1 pm/°C. Such vertical grating coupler and low loss MR-integrated components greatly promote a key element in biosensors and high-speed interconnect communication applications.