Saw resonator filter and duplexer utilizing SH waves, substrate edge reflection, and sub-interdigital transducer portions

A SAW resonator filter comprising:

• a piezoelectric substrate;
• and
• resonators arranged on the piezoelectric substrate, the resonators including a plurality of interdigital transducers having electrode fingers, wherein the interdigital transducers are arranged so as to be acoustically coupled to form a filter, wherein the interdigital transducers are divided into a plurality of sub-interdigital transducer portions, and wherein the sub-interdigital transducer portions are connected in series, and the resonators are arranged on the piezoelectric substrate to generate shear horizontal waves that are reflected by edges of the piezoelectric substrate.

A communication apparatus having a duplexer, wherein the duplexer comprises:

• a piezoelectric substrate;
• and
• first and second resonators arranged on the piezoelectric substrate, the first and second resonators including first and second interdigital transducers having electrode fingers, respectively, wherein the first and second interdigital transducers are acoustically coupled to form a filter, and wherein the first and second interdigital transducers are divided into a plurality of sub-interdigital transducer portions, respectively, and the first and second resonators are arranged on the piezoelectric substrate to generate shear horizontal waves that are reflected by edges of the piezoelectric substrate.