A diaphragm-free fiber-optic Fabry-Perot (FP) interferometric gas pressure sensor is designed and experimentally verified in this paper. The FP cavity was fabricated by inserting a well-cut fiber Bragg grating (FBG) hollow silica tube (HST) from both sides into casing. length between the ends of SMF HST changes with density. Using temperature decoupling method to improve accuracy high environments. An experimental system for measuring under different temperatures established verify...

This paper focuses on the design and fabrication of a high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit, which consists encapsulated pressure-sensitive chip, temperature compensation circuit circuit. A silicon insulation (SOI) material standard MEMS process are used in chip fabrication, electronic components adopted temperature-compensation circuits. The entire achieves hermetic seal can be operated long-term range -50 °C to 220 °C. Unlike...

In this study, a fiber-optic Fabry-Perot (FP) high-temperature pressure sensor based on sapphire direct bonding is proposed and experimentally demonstrated. The fabricated by of two-layer wafers, including diaphragm wafer cavity-etched wafer. composed head that contains vacuum-sealed cavity arranged as an FP multimode optical fiber. external can be measured detecting the change in length sensor. Experimental results demonstrate sensing capabilities for pressures from 20 kPa to 700 up 800°C.

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent health monitoring, and many areas everyday life. A passive sensor based on PCB (Printed Circuit Board) materials is reported this paper. The advantages of include simple mechanical structure, convenient processing, low-cost, easiness integration. temperature-sensitive structure a dielectric-loaded resonant cavity, consisting substrate....

In this study, a novel batch-producible fiber-optic Fabry-Perot (FP) pressure sensor based on low-temperature co-fired ceramic technology is proposed and experimentally demonstrated for high-temperature applications. The fabricated by inserting well-cut single-mode fiber (SMF) into zirconia ferrule, followed insertion of the overall structure an alumina head. FP cavity in formed placing end face SMF parallel to diaphragm. external can be detected demodulating length sensor. A theoretical...

In response to the growing demand for in situ measurement of pressure high-temperature environments, a high temperature capacitive sensor is presented this paper. A ceramic material-alumina used fabrication sensor, and prototype consists an inductance, variable capacitance, sealed cavity integrated alumina substrate using thick-film technology. The experimental results show that proposed has stability at 850 °C more than 20 min. characterization environments successfully demonstrated sensing...

The main limitation of high-temperature piezoresistive pressure sensors is the variation output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, equations independent parameter deviation among piezoresistors microelectromechanical sensor and residual stress caused by...

The silicon on insulator (SOI) high temperature pressure sensor is a novel with high-performance and high-quality. A structure of SOI high-temperature presented in this paper. key factors including doping concentration power are analyzed. process the designed critical parameters set appropriately. test result at room shows that nonlinear error below 0.1%, hysteresis less than 0.5%. High measuring results show can be used for from to 350 °C harsh environments. It offers reference development...

An in-line fiber optic Fabry–Perot (FP) sensor for high-temperature vibration measurement is proposed and experimentally demonstrated in this paper. We constructed an FP cavity a mass on single-mode fibers (SMFs) by fusion, together they were inserted into hollow silica glass tube (HST) to form sensor. The radial dimension of the was less than 500 μm. With its all-silica structure, has prospect measuring environments. In our test, had resonance frequency 165 Hz. voltage sensitivity system...

High temperature co-fired ceramics (HTCCs) have wide applications with stable mechanical properties, but they not yet been used to fabricate sensors. By introducing the wireless telemetric sensor system and ceramic structure embedding a pressure-deformable cavity, designed sensors made from HTCC materials (zirconia 96% alumina) are fabricated, their capacities for pressure measurement tested using interrogation method. Using fabricated sensor, study is conducted measure atmospheric in sealed...

An aluminum nitride (AlN) based patch antenna-type high-temperature wireless passive sensor is reported to operate as both a and an antenna, which integrates in situ measurement/sensing with remote communication at the same time. The small, easy manufacture, highly sensitive has high operating temperature; it can be used high-temperature, chemically corrosive other harsh environments. sensing mechanism of sensor, dielectric constant AlN ceramic substrate, increases rising temperature,...

A single crystalline magnesium oxide (MgO) MEMS-based fiber-optic Fabry-Perot (FP) pressure sensor was designed, fabricated and tested for 800 °C high-temperature environmental applications. In this article, MgO selected as the sensitive materials of optical owing to its high melting point, excellent mechanical properties at elevated temperatures. The head constructed by combining wet chemical etching with direct bonding. This MEMS process technique realized all-MgO structure, which is...

In this letter, we present a sapphire direct bonding method using plasma surface activation, hydrophilic pre-bonding, and high temperature annealing. Through the combination of inductively coupled etching process, vacuum-sealed cavity employable for applications is achieved. Cross-sectional scanning electron microscopy (SEM) research interface indicates that two pieces are well bonded structure stays intact. Moreover, tensile testing shows strength in excess 7.2 MPa. The advantage it free...

Fiber optic pressure sensors have been widely used in recent decades. Most of the fiber use gratings and Fabry-Perot cavity. However, they drawbacks achieving distributed sensing. In this paper, a lossless sensor based on structure composed two ratios polydimethylsiloxane (PDMS) single-mode is proposed. The PDMS has often as flexible structural material. When acting radially PDMS, internal driven to produce an axial strain larger range, optical frequency domain reflectometer (OFDR)...

A noncontact wireless passive pressure sensor based on alumina ceramic for measurement is presented in this paper. faithful signal harsh environment captured through sensing, and a novel antenna design method developed to increase the distance between sensor. The fabricated using no-co-fired technology, properties of platinum ensure feasibility high-temperature environments. experimental results show that coupled can be up 5.5 cm, designed sensor, featuring improved structural parameters,...

A wireless passive pressure measurement system for an 800 °C high-temperature environment is proposed and the impedance variation caused by mutual coupling between a read antenna LC resonant sensor analyzed. The consists of ceramic-based sensor, readout device phase interrogation, heat insulating material, composite temperature-pressure test platform. Performances are measured sufficiently, including sensitivity at room temperature, zero drift from temperature to °C, under high environment....

A novel Fabry-Perot (F-P) demodulation technique based on least square fitting for arbitrary reflectivity F-P sensors is proposed. The method was simulated and analyzed to verify feasibility of the algorithm. Two different finesse interferometers constructed with a reflector bracket were used make stability experiments stepping experiments. results show that can interrogate cavity length fineness in wide range, error less than 12 nm.

Electrochromic devices (ECDs) that display multicolor patterns have gradually attracted widespread attention. Considering the complexity in integration of various electrochromic materials and multi-electrode configurations, design patterned ECDs based on simple approaches is still a big challenge. Herein, it demonstrated vivid with broadened color hues via introducing carbon dots (CDs) into ion electrolyte layer. Benefiting from synergistic effect electrodes electrolytes, resultant presented...