Title:
SURFACE ACOUSTIC WAVE TRANSDUCER
Document Type and Number:
Japanese Patent JP3040928
Kind Code:
B2
Abstract:
PURPOSE: To invert the direction originated in natural single phase unidirectional transducer(NSPUDT) characteristics, to facilitate manufacture and to improve frequency characteristics and phase characteristics in a surface acoustic wave device using a piezoelectric substrate provided with the NSPUDT characteristics.
CONSTITUTION: On the piezoelectric substrate provided with the NSPUDT characteristics, the electrode fingers 21a and 22a of a positive electrode 21 and a negative electrode 22 as excitation electrodes are interdigitally arranged with the pitch of λ respectively so as to make a distance between the centers of the successive electrode fingers be approximately λ/2. Between the positive electrode finger 21a and the negative electrode finger 22a, the electrode finger 23a of a floating electrode 23 whose reflection coefficient is different from the electrode fingers is almost symmetrically arranged, the difference of the reflection coefficients of the excitation electrodes and the floating electrode is used and the direction based on the NSPUDT characteristics on the piezoelectric substrate is inverted.
Inventors:
Kazuhiko Yamanouchi
Masao Takeuchi
Hiroyuki Odagawa
Mitsuhiro Tanaka
Masao Takeuchi
Hiroyuki Odagawa
Mitsuhiro Tanaka
Application Number:
JP804895A
Publication Date:
May 15, 2000
Filing Date:
January 23, 1995
Export Citation:
Assignee:
Kazuhiko Yamanouchi
Masao Takeuchi
Nippon Insulator Co., Ltd.
Masao Takeuchi
Nippon Insulator Co., Ltd.
International Classes:
H03H9/145; (IPC1-7): H03H9/145
Attorney, Agent or Firm:
Akihide Sugimura (1 outside)