Capacitance-Type Micro Pressure Sensor Using Single-Crystalline Sapphire

Modeling of capacitance and sensitivity of a MEMS pressure sensor

In this paper modeling of capacitance and sensitivity for MEMS capacitive pressure sensor is presented. In capacitive sensor the sensitivity is proportional to deflection and capacitance changes versus pressure. Therefore first the diaphragm displacement, capacitance and sensitivity of sensor with square diaphragm have been modeled and then simulated using finite element method (FEM).  It can b...

An Investigation on Two Types of Crystalline Micro-diamond Film Coated Tools Lapping with Sapphire Wafer

Two types of micron-diamond films were prepared on YG6 substrate by hot filament chemical vapor deposition(HFCVD) method. Morphology and orientation of crystalline growth were evaluated by SEM and XRD. Diamond film coated tools and sapphire wafer’ surface before and after lapping experiment  were contrasted. The results indicated that a significant change in Raman spectrum of two types of micro...

A capacitance pressure sensor using a phase-locked loop.

We are using a Hercules (model #F4-4R, 100 psi) pressure sensor to measure the pressure between the foot and shoe. An interface circuit converts the capacitance change into voltage. Over the pressure range from 0 to 1300 kPa, the capacitance changes from 275 to 580 pF. A 555 timer circuit converts the capacitance into a frequency range from 30 to 63 kHz. A phase-locked loop (PLL) converts this ...

Single - Crystal Sapphire Optical Fiber Sensor Instrumentation

Fabrication of Wireless Micro Pressure Sensor Using the CMOS Process

In this study, we fabricated a wireless micro FET (field effect transistor) pressure sensor based on the commercial CMOS (complementary metal oxide semiconductor) process and a post-process. The wireless micro pressure sensor is composed of a FET pressure sensor, an oscillator, an amplifier and an antenna. The oscillator is adopted to generate an ac signal, and the amplifier is used to amplify ...