Claims
- 1. An end-surface reflection type surface acoustic wave filter comprising:a piezoelectric substrate including first and second reflection end-surfaces disposed substantially parallel to each other and spaced from each other by a predetermined distance, a top surface, a bottom surface, first and second piezoelectric substrate portions which extend from bottom ends of the first and the second reflection end-surfaces to outside of the filter, and first and second grooves or first and second recess portions open to the outside of the filter, the first and the second reflection end-surfaces and the first and the second piezoelectric substrate portions defining the first and the second grooves or the first and the second recess portions, respectively; a plurality of interdigital transducers disposed on the top surface of the piezoelectric substrate between the first and the second grooves or between the first and the second recess portions; and a layer which includes SiO2 and is arranged so as to cover said plurality of interdigital transducers.
- 2. An end-surface reflection type surface acoustic wave filter according to claim 1, wherein, when a wavelength of a surface acoustic wave which is to be used is represented by λ, and an electrode thickness of the interdigital transducer is represented by H, H/λ≦0.06 is satisfied.
- 3. An end-surface reflection type surface acoustic wave filter according to claim wherein, when a wavelength of a surface acoustic wave which is to be used is represented by λ, and an electrode thickness of the interdigital transducer is represented by H H/λ≦0.045 is satisfied.
Priority Claims (2)
Number |
Date |
Country |
Kind |
2001-246249 |
Aug 2001 |
JP |
|
2002-210355 |
Jul 2002 |
JP |
|
Parent Case Info
This application is a Continuation of U.S. patent application Ser. No. 10/218,017 filed Aug. 14, 2002, currently pending.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
5260913 |
Kadota et al. |
Nov 1993 |
A |
6185801 |
Kadota et al. |
Feb 2001 |
B1 |
6472798 |
Kishimoto |
Oct 2002 |
B2 |
6600391 |
Kadota et al. |
Jul 2003 |
B2 |
Continuations (1)
|
Number |
Date |
Country |
Parent |
10/218017 |
Aug 2002 |
US |
Child |
10/725872 |
|
US |