Surface acoustic wave filter

A surface acoustic wave filter comprising:

• a LiTaO3 piezoelectric substrate;
• and
• interdigital transducer electrodes disposed on the LiTaO3 piezoelectric substrate;
• wherein
• the surface acoustic wave filter is a ladder-type surface acoustic wave filter including series resonators and parallel resonators defined by the interdigital transducer electrodes and utilizes a leaky wave that propagates on the LiTaO3 piezoelectric substrate;
• wherein
• a bandwidth ratio that indicates a bandwidth of a passband of the surface acoustic wave filter is about 2.5% or greater;
• a cutoff frequency at which bulk wave radiation of one of the parallel resonators increases is in a frequency range higher than the passband;
• a normalized film thickness that is a ratio of a film thickness of the interdigital transducer electrodes of the parallel resonator to a repetitive pitch of a plurality of electrode fingers of the interdigital transducer electrodes of the parallel resonator is greater than or equal to about 9.0% and less than or equal to about 13.0%;
• and
• a duty ratio that is a ratio of a line width of the plurality of electrode fingers to a sum of the line width and a space width between the plurality of electrode fingers is greater than or equal to about 0.3 and less than or equal to about 0.8.