Wirelessly Powered High-Temperature Strain Measuring Probe Based on Piezoresistive Nanocrystalline Diamond Layers

Abstract

A high-temperature piezo-resistive nano-crystalline diamond strain sensor and wireless powering are presented in this paper. High-temperature sensors and electronic devices are required in harsh environments where the use of conventional electronic circuits is impractical or impossible. Piezo-resistive sensors based on nano-crystalline diamond layers were successfully designed, fabricated and tested. The fabricated sensors are able to operate at temperatures of up to 250°C with a reasonable sensitivity. The basic principles and applicability of wireless powering using the near magnetic field are also presented. The system is intended mainly for circuits demanding energy consumption, such as resistive sensors or devices that consist of discrete components. The paper is focused on the practical aspect and implementation of the wireless powering. The presented equations enable to fit the frequency to the optimal range and to maximize the energy and voltage transfer with respect to the coils' properties, expected load and given geometry. The developed system uses both high-temperature active devices based on CMOS-SOI technology and strain sensors which can be wirelessly powered from a distance of up to several centimetres with the power consumption reaching hundreds of milliwatts at 200°C. The theoretical calculations are based on the general circuit theory and were performed in the software package Maple. The results were simulated in the Spice software and verified on a real sample of the measuring probe.

Metrology and Measurement Systems

“…What is more, Tykhan et al [9] proposed a new type of piezoresistive pressure sensors for environments with rapidly changing temperature. Bouřa et al [10] proposed a wirelessly-powered high-temperature strain measuring probe based on piezoresistive nanocrystalline diamond layers, but the effect of applying an earth pressure box to test the pressure distribution proved unsatisfactory. The accuracy of test results was affected by its large size, too few test points, too much wiring, and stiffness greater than that of the measured medium.…”

Piezoresistivity of resin-impregnated carbon nanotube film at high temperatures

“…These CNT-based materials can be incorporated into other materials to serve as reinforcement and as strain sensor simultaneously, thereby obviating the need to use a metal foil strain gauge. However, composite materials for aviation applications are often subjected to severe environmental conditions, more specifically a wide range of temperatures [15,16]. Thus, the temperature dependence of the piezoresistive behaviour of CNT composites needs to be analysed, especially for use in a temperature-sensitive polymer matrix.…”