Patent ID: 7868717

Claim:
A transducer operating with surface acoustic waves, comprising: an acoustic track in which an acoustic wave can be propagated, the acoustic track having a transversal fundamental mode, the acoustic track being subdivided in a transversal direction into an excitation area and two peripheral areas; a first outside area and a second outside area bordering the acoustic track such that the acoustic track is arranged in the transversal direction between the first and second outside areas; the peripheral areas are configured such that the longitudinal phase velocity v RB of the acoustic wave in the respective peripheral area is greater than the longitudinal phase velocity v MB of the wave in the excitation area; wherein: the outside areas configured such that the longitudinal phase velocity v AU of the acoustic wave in the respective outside area is less than v MB , the peripheral areas and outside areas are configured such that (k y ) 2 >0 in the respective peripheral area and (k y ) 2 <0 in the respective outside area, where k y is the wave number of the transversal fundamental mode in the respective area; a width of the peripheral areas in the transversal direction is configured relative to a width of the excitation area such that k y is substantially constant in the excitation area and is less in absolute value by at least a factor of 10 than in the peripheral areas and the outside areas; and the width of the respective peripheral area in the transversal direction is between π/(4k y,RB ) and π/(2k y,RB ), where k y,RB is the wave number of the fundamental mode in the respective peripheral area.