Monitoring the tire pressure at cars using passive SAW sensors

In this paper, an AIN/free-standing nanocrystalline diamond (NCD) system is proposed in order to process high frequency surface acoustic wave (SAW) resonators for sensing applications. The main problem of synthetic diamond is its high surface roughness that worsens the sputtered AIN quality and hence the device response. In order to study the feasibility of this structure, AIN films from 150 nm up to 1200 nm thick have been deposited on free-standing NCD. We have then analysed the influence of the AIN layer thickness on its crystal quality and device response. Optimized thin films of 300 nm have been used to fabricate of one-port SAW resonators operating in the 10-14 GHz frequency range. A SAW based sensor pressure with a sensibility of 0.33 MHz/bar has been fabricated.

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“…8. The high sensitivity obtained here can utterly be tuned up by optimizing the device location within the diaphragm [35,36].…”

Section: Saw Pressure Sensormentioning

confidence: 98%

High precision pressure sensors based on SAW devices in the GHz range

Rodríguez-Madrid

Iriarte

Williams

et al. 2013

Sensors and Actuators A: Physical

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“…Consequently, applying SAW sensors in a tyre pressure and temperature monitoring system has been explored for their advantages in the sense that they have very small size and weight, can pass signals wirelessly, receive the required power wirelessly by the energy of the RF field (and therefore no local battery is needed), and can resist harsh environment conditions (Pohl et al, 1997(Pohl et al, , 1998Xiangwen et al, 2004;Zhang et al, 2004;Li et al, 2010). The working principle of SAW sensors is explained in detail in chapter five in Yurish and Gomes (2005).…”

Section: Surface Acoustic Wavementioning

confidence: 99%

A micro-capacitive pressure sensor design and modelling

Kubba

Hasson

Kubba

et al. 2016

J. Sens. Sens. Syst.

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Abstract. Measuring air pressure using a capacitive pressure sensor is a robust and precise technique. In addition, a system that employs such transducers lies within the low power consumption applications such as wireless sensor nodes. In this article a high sensitivity with an elliptical diaphragm capacitive pressure sensor is proposed. This design was compared with a circular diaphragm in terms of thermal stresses and pressure and temperature sensitivity. The proposed sensor is targeted for tyre pressure monitoring system application. Altering the overlapping area between the capacitor plates by decreasing the effective capacitance area to improve the overall sensitivity of the sensor ( C/C), temperature sensitivity, and built-up stresses is also examined in this article. Theoretical analysis and finite element analysis (FEA) were employed to study pressure and temperature effects on the behaviour of the proposed capacitive pressure sensor. A MEMS (micro electro-mechanical systems) manufacturing processing plan for the proposed capacitive sensor is presented. An extra-low power short-range wireless read-out circuit suited for energy harvesting purposes is presented in this article. The developed read-out circuitry was tested in terms of sensitivity and transmission range.

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“…These SAW-based sensors are used to measure a number of physical quantities: gas concentration [5][6][7][8], temperature, pressure [9][10][11][12][13], and mechanical quantities: torque of a rotating shaft [14], stress [15][16][17], acceleration [18][19] and vibrations [20][21]. All these SAW-based sensors work on the basis of measuring changes in the delay of a surface wave due to the impact of a physical quantity being measured on its speed and the propagation path.…”

Section: Figurementioning

confidence: 99%