Abstract
The fast-response and high-sensitivity surface acoustic wave sensor based on the hematoporphyrin (Hp) layer–lithium niobate (LiNbO 3) structure has been investigated. The amplitude and phase of the Hp–LiNbO 3 SAW delay line output signal were measured as functions of relative humidity (RH) at the steady-state conditions and as functions of time upon the step-like RH variation. Both the SAW attenuation and velocity strongly depend on the relative humidity (RH) due to water sorption by Hp film. At SAW frequency 86 MHz, the changes of −0.8 dB in SAW transmission loss and −3° in phase per 1% of RH were obtained, corresponding to 110 ppm/1% RH in relative SAW velocity change and 1.23 × 10 −3 per 1% RH in the change in the SAW attenuation per wavelength. The sensor exhibits fast response to the step jump up in humidity and fast recovery upon the abrupt humidity drop down with characteristic times of about 1 s. The applicability of the sensor for human breath monitoring is demonstrated.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
