Love-SAW sensors Technology Note

February 15th 2021: AWSensors is pleased to invite you to take a look to the its new Technology Note on Love-SAW sensors “AWSensors Love-SAW sensors“.

Summary of the Note

Advanced Wave Sensors (AWSensors) develops and markets various types of sensors: classical QCM, High Fundamental Frequency QCM, and Love-Surface Acoustic Wave (Love-SAW). Love-SAW sensors do not measure love, but they do measure other interesting properties of interfacial layers. This Note is dedicated to explaining the basics of the operation of these less known acoustic sensors.

 

Love-SAW sensor

Introduction to Love-SAW sensors

Love waves are shear horizontally (SH) polarized surface acoustic waves. They are named after Augustus Edward Hough Love, who predicted them mathematically in 1911, and appear in fields as distinct as seismology and sensing [1].

Figure 1. a) Piezoelectric material, such as quartz, cut at a certain angle relative to the crystallographic axis, is used as a substrate in the construction of the Love-SAW sensors which basic structure is shown in b) (Taken from [2]).

Love-SAW sensors use a piezoelectric substrate (like quartz), in which the surface acoustic waves are excited by applying electrical current in a specific direction relative the crystallographic orientation of the piezoelectric material (see Figure 1a). The waves are then confined into the guiding layer overlaying the piezoelectric substrate. The structure of such a sensor is shown in Figure 1b where the current is applied through the so-called interdigitated transducers (IDTs), located between the substrate and the guiding layer. A standing Love wave is generated in the space between the IDTs (D in Figure 2), defining the sensing area. The condition for the existence of these waves is that the shear velocity in the guiding layer is less than that in the substrate. It is this difference in the mechanical properties between the guiding layer and the substrate that slows down the wave propagation velocity and traps the acoustic energy in the guiding layer keeping the wave energy near the surface. The sensitivity of this device is determined by the degree of wave confinement in the guiding layer. Thus, the higher the confinement of the wave in the guiding layer, the higher the sensitivity of the device is.

Love-SAW sensors typically operate at frequencies of hundreds of MHz. The operating frequency of a Love-SAW sensor is defined by the materials of its structure, the periodicity of the IDTs, λ in Figure 2, and the guiding layer thickness, d [2].

Key advantages of Love-SAW devices include efficient operation in liquids, mechanical stability (robustness), and high sensitivity (due to the high operating frequency by only changing the IDTs periodicity). Key limitations include a need for calibration due to the lack of simple, predictive model describing SAW wave propagation akin to the Sauerbrey relationship in QCMD or Lorentz-Lorenz and de Feijter’s relationships in ellipsometry. [3–5]

Continue reading by downloading the full Application Note (below) …


Download Full Application Note

You can download the full Love-SAW Technology Note in pdf file from this link or download it from our Thecnology Web Page where you can find this and the rest of our Technology Notes.

Other references about Love-SAW sensors

 

EXPORNET-IVACE

January 31st 2021:

AWSensors was granted with the EXPORNET aid, managed by IVACE, Generalitat Valenciana, Spain, for the improvement of its Digital Marketing.

Advanced Waves Sensors S.L. (AWSensors) ha sido beneficiaria del Fondo Europeo de Desarrollo Regional (FEDER) dentro del Program Operativo FEDER de la Comunitat Valenciana 2014-2020  cuyo objetivo es mejorar la competitividad de las PYMES valencianas. El programa de asesoramiento en materia de internacionalización del Cheque Tutorías Inernacionalización para el ejercicio 2021, gestionado por el IVACE, en el que participará AWSensors este año es el de Marketing Digital Internacional (EXPORNET). El programa EXPORNET consiste en un asesoramiento especializado en posicionamiento internacional, a través
del uso de Internet como herramienta comercial de ámbito internacional, mediante el diseño de un plan de marketing digital.

 


 

X4-instrument

X4 Launching

January 19th 2021: X4 launching

AWSensors is pleased to announce the launching of its new Advanced Multichannel QCMD system, the X4 Instrument, which allows the users to boost their productivity.

X4 Instrument


Visit X4 launching Landing-page

Learn more about this new instrument in its landing page.