ACOUSTIC SURFACE WAVE DEVICES

• US 3,801,935 A
• Filed: 07/12/1972
• Issued: 04/02/1974
• Est. Priority Date: 07/21/1971
• Status: Expired due to Term

• Current Assignee: Richard Frank Mitchell
• Original Assignee: Richard Frank Mitchell
• Inventors: Mitchell, Richard Frank
• Primary Examiner(s): Gensler, Paul L.
• Application Number:
  US05/271,164
• Time in Patent Office: 629 Days
• Field of Search: 333/3R,72 310/9.8
• US Class Current: 333/193
• CPC Class Codes: H03H 9/02818 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/1455 constituted of N parallel or series transducers

Abstract

An acoustic surface wave device is provided with an interdigital transducer divided into a plurality of sections, the sections being connected in series. The transducer thus presents a higher and therefore more convenient terminal impedance. A filter embodiment is also shown in which two end sections of a transducer array are connected in series, thus reducing the source strengths of the electrodes without the disadvantage of either making the electrodes too narrow with consequent production errors, or with too short an overlap giving rise to errors due to end effects.

Claims

1. A surface-wave filter, comprising a body of piezoelectric material, a receiving transducer on the acoustic wave propagation surface of the piezoelectric material, at least three interdigitized electrode launching transducer components sequentially arranged along the direction of acoustic wave propagation on the acoustic wave propagation surface of the piezoelectric material, a first electrical conductor connecting the two launching transducer components at the ends of the sequential arrangement in series, additional electrical conductors connecting an inner launching transducer component located between the end launching transducer components in parallel with the series connected end launching transducer components.