A filter includes a piezoelectric substrate, and interdigital transducers
(IDTs) that are formed on the piezoelectric substrate. At least one of
the IDTs has a main electrode finger pattern that is weighted. The IDT
having the main electrode finger pattern also has a sub electrode finger
pattern that is connected in parallel to the main electrode finger
pattern, and generates a surface acoustic wave that cancels a surface
acoustic wave caused by leakage electric fields generated in the main
electrode finger pattern.