Vectron International Gmbh & Co. Kg

Leibniz-institut Fuer Festkoerper-und Werkstoffforschung Dresden E.v.

Leibniz-institut Fuer Festkoerper-und Werkstofforschung Dresden E.v.

Sergey Biryukov

Guenter Martin

Bert Wall

Manfred Weihnacht

Bernd Steiner

Alexander Darinski

A transducer has natural unidirectionality for surface acoustic waves. An interdigital electrode structure is arranged on a piezoelectric crystal substrate and is constructed with interdigital transducers including collecting electrodes and fingers. At least two of the fingers form a transducer cell, which includes at least one excitation center for exciting an electrical potential wave and at least one reflection center for reflecting electrical potential waves. The fingers are oriented perpendicularly to a direction R parallel to a 1- or 3-fold rotational axis of the substrate crystal and the derivative dv/d&#x3b8;=0 applies to R, wherein v is the phase velocity of the surface wave and &#x3b8; is an angular deviation of the perpendicular to the finger direction from the direction R.

Transducer having natural unidirectionality for surface acoustic waves

The invention relates to waveguide components based on acoustic surface waves, comprising at least one interdigital converter for exciting acoustic surface waves in a piezoelectric substrate or a piezoelectric layer. The object of the invention is to change known waveguide components, comprising at least one interdigital converter for exciting acoustic surface waves in a piezoelectric substrate or a piezoelectric layer, such that no reflectors are necessary with an otherwise equivalent function. The inventive waveguide components are characterized in that the interdigital converter(s) a) is or are disposed at a defined distance over the piezoelectric substrate or the piezoelectric layer for exciting wave fields, or b) is or are in contact with the piezoelectric substrate or the piezoelectric layer, wherein in version a) the piezoelectric substrate is designed as a ring and the piezoelectric layer is designed as a circular region. In case of version b), the interdigital converter and/or the piezoelectric layer form circular regions. The components can be used for example as resonators, filters, oscillators and sensors.

Waveguide components on the basis of acoustic surface waves, and their use

A transducer for surface acoustic waves, and a resonator and a filter for surface acoustic waves having the transducer are provided. The transducer for surface acoustic waves has cells containing two electrode fingers per cell, wherein the transducer exhibits unidirectional behavior for propagation directions of the surface acoustic waves parallel to highly symmetrical directions of the crystal substrate. Each of two electrodes have a plurality of electrode fingers, the electrode fingers having center axes extending parallel to their longitudinal axes and being spaced apart from center axes of adjacent electrode fingers of the same electrode by a distance which equals the ratio of the velocity of the surface acoustic wave and the cut-off frequency of the transducer. The electrode fingers of both electrodes define a plurality of cells each consisting of two fingers.

Transducer for surface acoustic waves and a resonator and a filter having said transducer

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Bannewitz, Germany

Sergey Biryukov