Liang Ting

Design, fabrication and characterization of pyroelectric thin film and its application for infrared gas sensors

Prepared by a sol–gel process, the lead zirconate titanate (PZT) (PbZr0.3Ti0.7O3) thin film, which is chosen as an infrared sensing film, uses lead acetate trihydrate, zirconium acetylacetone, acetylacetone, and titanium isopropoxide as starting materials. The pyroelectric infrared sensor with the PZT thin film has been successfully fabricated. The fabrication process of the device is discussed in detail. A new Au Pt–PZT–Pt infrared detecting structure on silicon substrate with a micro bridge is designed. Under the response and reference dual-element configuration, undesirable signals, caused by vibration, ambient temperature change, and sunlight, are cancelled out at the input of the preamplifier circuit. The dual-element structural design of the device is discussed and analyzed in detail. In order to realize our purpose to use this detector to monitor gas concentration, we designed a detection set-up in the light of a certain gas which absorbs infrared radiation at specific wavelengths. The gas concentration is obtained by designing a weak signal detect circuit and data arithmetic. The first measurement for methane is reported. Experimental result shows the ability of methane detection of the detector based on the infrared sensor element. & 2008 Elsevier Ltd. All rights reserved.

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.

A novel MEMS SiC pressure sensor for high-temperature application

This paper designs a SiC (Silicon Carbide) non-contact capacitive pressure sensor for high-temperature application. The sensor is proposed to operate at high temperature environment due to its SiC -glass paste- SiC sandwiched structure. Mechanical performance of the sensor is verified by finite element analysis software and its MEMS process flow is also presented in detail. The SiC capacitive chip and external inductor coils composed a LC circuit for the purpose of extraction and measurement of pressure signal. The conversion between external pressure signal and resonance frequency signal of LC circuit is successfully achieved by wireless passive pressure measurement technology, providing a new way to solve the nonlinear test of variable-gap capacitive pressure sensor. Test result shows that resonant frequency and applied pressure have an inverse relationship under a range of 0-200kPa with a high sensitivity of 10.6 kHz/kPa. The design idea of the novel sensor provides a reference for the development of high-temperature pressure measurement.

Design of Wireless Coupling Signal Transmission Antenna and Impedance Matching

In this work, an extremely compact antenna is designed and used for wireless coupling signal transmitting. This antenna is constituted by a planar spiral inductance and a capacitance. The inductance is designed with 10 turns, 0.5mm turn width, 0.5mm turn spacing and 21mm inner diameter. Calculate the planar inductance parameter and use ADS (Advanced Design System) software to match the antenna impedance at the center frequency of 8.54MHZ. Structuring the impedance matches circuit. Compare the voltage or impedance changes before and after the antenna impedance matching, and optimize the antenna impedance matching network.