An interdigital transducer (IDT) is a device that consists of two interlocking comb-shaped arrays of metallic electrodes (in the fashion of a zipper). These metallic electrodes are deposited on the surface of a

piezoelectric Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied stress (mechanics), mechanical s ...

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

, such as

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

lithium niobate Lithium niobate () is a synthetic salt consisting of niobium, lithium Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperatur ...

, to form a periodic structure.Difference Between Active and Passive Transducer
Retrieved 13 February 2023.

Function

IDTs primary function is to convert electric signals to

surface acoustic wave A surface acoustic wave (SAW) is an acoustic wave traveling along the surface of a material exhibiting elastic (solid mechanics), elasticity, with an amplitude that typically decays exponentially with depth into the material, such that they are c ...

s (SAW) by generating periodically distributed mechanical forces via piezoelectric effect (an input transducer). The same principle is applied to the conversion of SAW back to electric signals (an output transducer). These processes of generation and reception of SAW can be used in different types of SAW signal processing devices, such as band pass filters, delay lines, resonators, sensors, etc. IDT was first proposed by Richard M. White and Voltmer in 1965.

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Function

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Further reading