A novel structure of the resonant pressure sensor is presented in this paper, which tactfully employs intercoupling between dual pressure-sensing diaphragms and a laterally driven resonant strain gauge. After the resonant pressure sensor principle is introduced, the coupling mechanism of the diaphragms and resonator is analyzed and the frequency equation of the resonator based on the triangle g...

This paper documents the manufacture and testing of a humidity sensor based on a combination of In2O3/SiO. A number of different sensor samples have been produced by thermal deposition and the effect of varying the vacuum pressure has also been investigated. The AC and DC conduction mechanisms have been investigated. From the AC conduction studies, the tunneling conduction mechanism has been ob...

The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the ...

In this study, we develop a clamped-clamped beam-type piezoelectric vacuum pressure sensing element. The clamped-clamped piezoelectric beam is composed of a PZT layer and a copper substrate. A pair of electrodes is set near each end. An input voltage is applied to a pair of electrodes to vibrate the piezoelectric beam, and the output voltage is measured at the other pair. Because the viscous fo...

A new structure thermal vacuum sensor with two pn junction diodes, Th-A and Th-B, as a high sensitive temperature sensor working like a thermistor and a micro heater formed on a micro air‒bridge is proposed. The micro air‒bridge is separated into two regions of A and B. The Th-A measures the temperature of the micro-heater formed on the region A and the Th-B does that of the region B which is c...

The fabrication of SiC MEMS pressure sensor based on novel vacuum-sealed method is presented in this paper. The sensor was fabricated using surface micromachining. Due to its excellent mechanical properties and high chemical resistance, PECVD (Plasma Enhanced Chemical Vapor Deposition) SiC was chosen as structural material. Polyimide is the sacrificial layer which solve stiction problem in proc...

This paper will discuss the results obtained with a first prototype of a completely passive and wireless low pressure sensor. The device is a heat conductivity gauge, based on a wireless and passive SAW temperature sensor. The required heating energy is applied to the sensor using inductive coupling. The prototype was successfully tested in a vacuum chamber. Its equilibrium temperature changed ...

........................................................................................i Acknowledgements ....................................................................................................... ii Executive Summary .......................................................................................................1 1. Introduction ............................................