SAW Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

D

Differential structure

Differential structure

Addition of a reference SAW device on a sensor chip, to provide a differential measurement that compensates for unwanted effects due to other physical parameter variations. For example, a differential temperature sensor uses two resonators operating at two different frequencies. The frequency difference (being furthermore less sensitive to ageing) is considered as input data for temperature computation.

Direct piezoelectric effect

Direct piezoelectric effect

Internal generation of electrical charge resulting from an applied mechanical stress

I

IDT Inter Digital Transducer

IDT Inter Digital Transducer

Device which consists of two interlocking comb-shaped metallic coatings applied to a piezoelectric substrate. IDTs are primarily used to convert microwaves to surface acoustic waves (SAW).

Inverse or reverse piezoelectric effect

Inverse or reverse piezoelectric effect

Internal generation of a mechanical stress resulting from an applied electrical field

M

Mounting

Mounting

Assembly of packaged sensor chip on material/components allowing antenna connection and sensor fixation for industrial use (for example: probes with screw mounting)

P

1 port SAW delay line

1 port SAW delay line

Reflective SAW device based on piezoelectric material on which are deposited one IDT (input/output transducer) and reflectors or other IDTs separated by certain distances from the input/output transducer in order to generate different delayed signals.

2 port SAW delay line

2 port SAW delay line

SAW device based on piezoelectric material on which are deposited two IDTs (input/output transducers) separated by a certain distance generating a delayed signal due to propagation time between the two transducers.

Package

Package

Material/components assembly where the sensor chip (sensitive element) is incorporated for protection and easy mounting in sensing systems. Example: ceramic package, metallic package, all-quartz package.

Piezoelectricity

Piezoelectricity

The charge which accumulates in certain solid materials like crystals or ceramics in response to applied mechanical strain, result of piezoelectric effect.

Piezoelectric effect

Piezoelectric effect

Linear electromechanical interaction between the mechanical and the electrical state in crystalline materials with no inversion symmetry.

R

Radio waves

Radio waves

 A type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Like all other electromagnetic waves, they travel at the speed of light. Naturally-occurring radio waves are made by lightning, or by astronomical objects. Artificially-generated radio waves are used for fixed and mobile radio communication, broadcasting, radar and other navigation systems, satellite communication, computer networks and innumerable other applications like SAW sensing.

Rayleigh surface acoustic wave

Rayleigh surface acoustic wave

 A wave propagating along the plane surface of an isotropic solid half-space, with amplitude decaying exponentially away from the surface. The solution needs to satisfy the condition that there is no traction on the surface, and to do this it has two components corresponding to bulk shear and longitudinal waves. The wave is non-dispersive, with a velocity a little less than that of the bulk shear wave. The motion of the material is in the sagittal plane, that is, the plane containing the surface normal and the propagation direction. (David Morgan)

RF Radio-frequency

RF Radio-frequency

 A rate of oscillation in the range of about 30 kHz to 300 GHz, which corresponds to the frequency of electrical signals normally used to produce and detect radio waves.

S

SAW Surface Acoustic Waves

SAW Surface Acoustic Waves

Acoustic waves propagating on the surface of a material (like piezoelectric material) exhibiting elasticity, with amplitude that typically decays exponentially with depth into the substrate.

SAW Resonator

SAW Resonator

SAW device based on piezoelectric material on which is deposited at least one  Inter Digital Transducer (IDT) surrounded by a sufficient number of reflectors in order to create a resonant cavity.

Sensor chip (or sensitive element)

Sensor chip (or sensitive element)

Die using a piezoelectric substrate incorporating SAW devices such as resonators or delay lines used to convert changes of physical parameters such as mechanical stress or temperature into electrical signals.

Partial contribution of Wikipedia

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SENSeOR Profile

SENSeOR exploits Surface Acoustic Waves (SAW) to conceive unique-patented wireless passive temperature sensors. SENSeOR is a 10-year old start-up spirit French company, part of WIKA Group since 2012. Its expert engineer team provides field-engineering services and customized developments in addition to its standard sensor portfolio, in a simple and comprehensive monitoring platform, for Industry and Energy applications. SENSeOR is a member of the French association “Think Smartgrids, French solutions for smart grids” and is part of "La French Tech - Clean Tech".