Multi-mode surface acoustic wave filter with slanted acoustic reflectors

A method of filtering a radio frequency signal with a multi-mode surface acoustic wave filter, the method comprising:

• providing a radio frequency signal to the multi-mode surface acoustic wave filter;
• filtering the radio frequency signal with the multi-mode surface acoustic wave filter, the multi-mode surface acoustic wave filter including a plurality of longitudinally coupled interdigital transducer electrodes and first and second acoustic reflectors on opposing sides of the plurality of longitudinally coupled interdigital transducer electrodes, the second acoustic reflector being a mirrored version of the first acoustic reflector that is mirrored about an aperture direction, a first interdigital transducer electrode of the longitudinally coupled interdigital transducer electrodes including interdigital transducer electrode fingers having substantially uniform pitch, the first acoustic reflector including acoustic reflector fingers with slanted pitches and extending from a bus bar, the slanted pitches including three different spacings between different portions of adjacent acoustic reflector fingers of the acoustic reflectors, the three different spacings including a first spacing and a second spacing, the different portions of the adjacent acoustic reflector fingers including a first portion with the first spacing and second and third portions with the second spacing, the second and third portions being on opposing sides of the first portion, and the different portions of the adjacent acoustic reflector fingers each extending substantially perpendicular to the bus bar;
• and
• during the filtering, suppressing a spurious response due to shear horizontal mode of the multi-mode surface acoustic wave filter with the acoustic reflectors of the multi-mode surface acoustic wave filter.

A packaged module comprising:

• a multi-mode surface acoustic wave filter on a packaging substrate, the multi-mode surface acoustic wave filter configured to filter a radio frequency signal, the multi-mode surface acoustic wave filter including a plurality of longitudinally coupled interdigital transducer electrodes and first and second acoustic reflectors on opposing sides of the plurality of longitudinally coupled interdigital transducer electrodes, the second acoustic reflector being a mirrored version of the first acoustic reflector that is mirrored about an aperture direction, a first interdigital transducer electrode of the plurality of longitudinally coupled interdigital transducer electrodes including interdigital transducer electrode fingers having substantially uniform pitch, the first acoustic reflector including acoustic reflector fingers with slanted pitches and extending from a bus bar, the slanted pitches including three different spacings between different respective portions of adjacent acoustic reflector fingers of the acoustic reflector fingers, the three different spacings including a first spacing and a second spacing, the different respective portions of the adjacent acoustic reflector fingers including a first portion with the first spacing and second and third portions with the second spacing, the second and third portions being on opposing sides of the first portion, and the different portions of the adjacent acoustic reflector fingers each extending substantially perpendicular to the bus bar;
• and
• other circuitry on the packaging substrate and in communication with the multi-mode surface acoustic wave filter.