Recent developments in surface acoustic wave sensors

Şchiopu, Paul; Cristea, Ionica; Grosu, Neculai; Craciun, Alexandru

doi:10.1117/12.823700

Cited by 5 publications

(2 citation statements)

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“…This acoustic wave propagates at the surface of the substrate until reaching the output IDT, also called the receiver. This electrical/mechanical conversion is used for various purposes in SAW systems, such as sensors, selective filters and delay lines [ 41 , 42 , 43 ].…”

Section: Methodsmentioning

confidence: 99%

Effect of Partial Ba Substitutions on the Crystallization of Sr2TiSi2O8 (STS) Glass–Ceramics and on the Generation of a SAW Signal at High Temperatures

et al. 2021

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Because of their characteristics, including a d33 of 10–15 pC/N and high stability up to temperatures over 1000 °C, polar glass–ceramics containing fresnoite crystals can be regarded as highly effective materials for applications requiring piezoelectricity at high temperatures. In the present paper we investigate barium substitutions in an Sr-fresnoite (STS) glass–ceramic. Two aspects are studied: first, the effect of the substitution on the preferential orientation of the crystallization, and second, the ability of the glass–ceramics to generate and propagate surface acoustic waves (SAW) at high temperatures. XRD analyses show that a 10 at.% substitution of Ba allows us to keep a strong preferential orientation of the (00l) planes of the fresnoite crystals down to more than 1 mm below the surfaces. Higher substitution levels (25 and 50 at.%), induce a non-oriented volume crystallization mechanism that competes with the surface mechanism. SAW devices were fabricated from glass–ceramic substrates with 0, 10 and 25 at.% Ba substitutions. Temperature testing reveals the high stability of the frequency and delay for all of these devices. The glass–ceramic with a 10 at.% Ba substitution gives the strongest amplitude of the SAW signal. This is attributed to the high (00l) preferential orientation and the absence of disoriented volume crystallization.

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Section: Methodsmentioning

confidence: 99%

Effect of Partial Ba Substitutions on the Crystallization of Sr2TiSi2O8 (STS) Glass–Ceramics and on the Generation of a SAW Signal at High Temperatures

et al. 2021

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“…Surface acoustic wave (SAW) [ 1 ] devices have already been successfully applied as sensors in analytical chemistry [ 2 , 3 ], because their high resonance frequency leads to excellent sensitivity [ 4 - 7 ]. The concept can be developed further by including means to distinguish different devices in multisensory environments.…”

Section: Introductionmentioning

confidence: 99%

SAW RFID-Tags for Mass-Sensitive Detection of Humidity and Vapors

Lieberzeit

Palfinger

Dickert

et al. 2009

Sensors

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One-port surface acoustic wave (SAW) devices with defined reflector patterns give characteristic signal patterns in the time domain making them identifiable and leading to so-called RFID-Tags. Each sensor responds with a burst of signals, their timed positions giving the identification code, while the amplitudes can be related to the analyte concentration. This paper presents the first combination of such a transducer with chemically sensitive layer materials. These include crosslinked polyvinyl alcohol for determining relative humidity and tert-butylcalix[4]arene for detecting solvent vapors coated on the free space between the reflectors. In going from the time domain to the frequency domain by Fourier transformation, changes in frequency and phase lead to sensor responses. Hence, it is possible to measure the concentration of tetrachloroethene in air down to 50 ppm, as well as 1% changes in relative humidity.

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