End face reflection type surface wave resonator

A method of fabricating an end face reflection type surface wave resonator, comprising the steps of:

• forming a piezoelectric substrate comprising first and second major surfaces in opposed position to one another, third and fourth surfaces in an opposed position to one another, a first end face for reflecting a surface wave, and a second end face for reflecting the surface wave, said first and second end faces being in an opposed position to one another and extending to said third and fourth surfaces at their respective edges;
• forming an interdigital transducer on said first major surface of said piezoelectric substrate having a plurality of electrode fingers, said plurality of electrode fingers extending in a direction which bisects said third and fourth surfaces, the edges of outermost electrode fingers being in contact with the edges of said first and second end faces respectively, said outermost electrode fingers having a width of about .lambda./8, the remaining electrode fingers having a width of about .lambda./4;
• forming a first channel having a depth extending from said first major surface toward said second major surface and a length extending from said third surface to said fourth surface of said piezoelectric substrate in a direction orthogonal to the surface wave propagating direction, said first channel forming at least one of said first and second end surfaces on at least one side of said interdigital transducer;
• and
• forming a barrier further from said interdigital transducer than said first channel, said barrier dividing an unused portion of said piezoelectric substrate from said end face reflection type surface wave resonator.

An end face reflection type surface wave resonator producing an SH-type surface wave, comprising:

• a piezoelectric substrate of substantially rectangular shape comprising first and second surfaces in opposed position to one another, third and fourth surfaces in an opposed position to one another, a first end face for reflecting a surface wave, and a second end face for reflecting the surface wave, said first and second end faces being in an opposed position to one another and extending to said third and fourth surfaces at their respective edges;
• an interdigital transducer formed on said first surface of said piezoelectric substrate comprising a first and second set of electrode fingers, said electrode fingers positioned in interdigitized relationship with one another and extending in a direction substantially parallel to said first and second end surfaces;
• and
• a first channel having a depth extending from said first surface toward said second surface and a depth extending from said third surface to said fourth surface of said piezoelectric substrate in a direction orthogonal to the surface wave propagating direction, said first channel forming at least one of said first and second end surfaces of said surface wave resonator.