Surface acoustic wave device using a leaky surface acoustic wave with an optimized cut angle of a piezoelectric substrate

A surface acoustic wave filter, comprising:

• a piezoelectric substrate of a single crystal LiTaO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Al as a primary component, said electrode pattern including an interdigital electrode;
• said electrode pattern forming a resonator and having a thickness in a range of about 0.03-0.15 times a wavelength of a surface acoustic wave excited on said surface of said piezoelectric substrate;
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle more than 39.degree. and less than about 46.degree..

A surface acoustic wave resonator, comprising:

• a piezoelectric substrate of a single crystal LiTaO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Al as a primary component, said electrode pattern including an interdigital electrode;
• said electrode pattern having a thickness in a range of about 0.03-0.15 times a wavelength of a surface acoustic wave excited on said surface of said piezoelectric substrate;
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle more than 39.degree. and less than about 46.degree.;
• said interdigital electrode including a first electrode group and a second electrode group, said first electrode group including a first group of electrode fingers provided on said surface of said piezoelectric substrate and connected commonly to a first terminal, said second electrode group including a second group of electrode fingers provided on said surface of said piezoelectric substrate and connected commonly to a second terminal, said first and second group of electrode fingers being disposed such that a second group electrode finger is interposed between a pair of first group of electrode fingers.

A surface acoustic wave device, comprising:

• a piezoelectric substrate of a single crystal LiTaO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Au as a primary component;
• said electrode pattern forming a resonator and having a thickness in a range of 0.004-0.021 times a wavelength of a surface acoustic wave excited on said surface of said piezoelectric substrate;
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle more than 39.degree. and less than about 46.degree..

A surface acoustic wave device, comprising:

• a piezoelectric substrate of a single crystal LiTaO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Cu as a primary component;
• said electrode pattern forming a resonator and having a thickness in a range of 0.009-0.045 times a wavelength of a surface acoustic wave excited on said surface of said piezoelectric substrate;
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle more than 39.degree. but less than about 46.degree..

A surface acoustic wave device, comprising:

• a piezoelectric substrate of a single crystal LiNbO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Au as a primary component;
• said electrode pattern having a thickness in a range of 0.005-0.017 times a wavelength of a surface acoustic wave excited on said surface of said piezoelectric substrate;
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle larger than 66.degree. but smaller than about 74.degree..

A surface acoustic wave device, comprising:

• a piezoelectric substrate of a single crystal LiNbO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Cu as a primary component;
• said electrode pattern having a thickness in a range of 0.012-0.036 times a wavelength of a surface acoustic wave excited on said surface of said piezoelectric substrate;
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle larger than 66.degree. but smaller than about 74.degree..

A surface acoustic wave device, comprising:

• a piezoelectric substrate of a single crystal LiNbO.sub.3 ;
• and
• an electrode pattern provided on a surface of said piezoelectric substrate and containing Al as a primary component;
• said electrode pattern having a thickness in a range of about 0.04-0.12 times a wavelength of a surface acoustic wave excited on said substrate,
• said piezoelectric substrate having an orientation rotated about an X-axis thereof, from a Y-axis thereof, toward a Z-axis thereof, with a rotational angle in a range larger than 66.degree. but smaller than about 74.degree..