Remotely interrogated MEMS pressure sensor

Ibrahim, Amr (2012) Remotely interrogated MEMS pressure sensor. PhD thesis, University of Glasgow.

Abstract

This thesis considers the design and implementation of passive wireless microwave readable pressure sensors on a single chip. Two novel-all passive devices are considered for wireless pressure operation.
The first device consists of a tuned circuit operating at 10 GHz fabricated on SiO2 membrane, supported on a silicon wafer. A pressure difference across the membrane causes it to deflect so that a passive resonant circuit detunes. The circuit is remotely interrogated to read off the sensor data. The chip area is 20 mm2 and the membrane area is 2mm2 with thickness of 4 µm. Two on chip passive resonant circuits were investigated: a meandered dipole and a zigzag antenna. Both have a physical length of 4.25 mm. the sensors show a shift in their resonant frequency in response to changing pressure of 10.28-10.27 GHz for the meandered dipole, and 9.61-9.58 GHz for the zigzag antenna. The sensitivities of the meandered dipole and zigzag sensors are 12.5 kHz and 16 kHz mbar, respectively.
The second device is a pressure sensor on CMOS chip. The sensing element is capacitor array covering an area of 2 mm2 on a membrane. This sensor is coupled with a dipole antenna operating at 8.77 GHz. The post processing of the CMOS chip is carried out only in three steps, and the sensor on its own shows a sensitivity of 0.47fF/mbar and wireless sensitivity of 27 kHz/mbar. The MIM capacitors on membrane can be used to detune the resonant frequency of an antenna.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Pressure sensor, MEMS, CMOS-MEMS
• Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
• Colleges/Schools: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Supervisor's Name: Cumming, Prof. David
• Date of Award: 2012
• Depositing User: Mr Amr Ibrahim
• Unique ID: glathesis:2012-4149
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 22 Apr 2013 14:21
• Last Modified: 22 Apr 2013 14:26
• URI: https://theses.gla.ac.uk/id/eprint/4149