Abstract: An interdigital surface acoustic wave transducer comprises a substrate having at least two areas. One area has piezoelectric properties. Laid down on it is a main row with electrodes. The other area has no piezoelectric properties and carries an additional row with electrodes. Each row comprises two groups of electrodes arranged in parallel with one another. The electrodes of first groups of the rows are connected electrically to respective current-conducting pads. The electrodes of second groups of the rows are connected conductively to one another and are positioned between the electrodes of the first groups of the rows. As a result, overlap portions of the electrodes of the two groups are formed which have a constant length in the main row and a variable length in the additional row.

Abstract: An acoustic surface wave filter includes a coupling element to transmit acoustic surface waves from a first acoustic channel to a second acoustic channel and simultaneously form the amplitude-frequency characteristic of the filter. The coupling element comprises two rows of electrodes. Each of these rows is arranged in a respective acoustic channel and has two group of electrodes which are respectively arranged parallel with electrodes of an input interdigitated converter and an output interdigitated converter, respectively, which are arranged in the first acoustic channel and the second acoustic channel, respectively. The electrodes of the first group of each row of the coupling element are respectively arranged between the electrodes of the second group of the same row and both form overlapping portions of a variable length in at least one row; this row corresponds to the row of electrodes of the input converter having overlapping portions of a constant length.

Abstract: An acoustic surface wave filter comprises an input and output acoustic surface wave transducers arranged on a piezoelectric substrate in spaced acoustic channels and a coupling element for the acoustic channels of the input and output transducers, said element being arranged on the same substrate. The coupling element includes three rows of electrodes, two of which are located respectively in the acoustic channels of the input and output transducers while the third one is positioned therebetween. Each row has two groups of electrodes. The electrodes of the rows disposed in the acoustic channels of the input and output transducers are arranged in parallel to the electrodes of its transducer. The electrodes of one of the groups of these rows are interconnected through a current conducting bus.

Abstract: An acoustic surface wave interdigital transducer comprises a main and auxiliary rows of electrodes arranged on a piezoelectric substrate. The main row of electrodes comprises a first group of electrodes galvanically connected to a first contact area and a second group of electrodes parallel to the electrodes of the first group and disposed therebetween so that there are formed overlapping portions having the same length. The auxiliary row of electrodes comprises a third group of electrodes galvanically coupled to the second contact area and a fourth group of electrodes parallel to the electrodes of the third group connected directly to the corresponding electrodes of the second group of the main row and disposed between the electrodes of the third group so as to form overlapping portions of electrodes of both groups, said portions having a variable length. The electrodes of the second group of the main row are connected to the second contact area through capacitances.