Surface acoustic wave resonator, acoustic wave filter, and multiplexer

Abstract

A surface acoustic wave resonator includes one IDT electrode and reflectors. When a distance between an electrode finger Fe(k) and an electrode finger Fe(k+1) is defined as a k-th electrode finger pitch, in an electrode finger Fe(k−1), the electrode finger Fe(k), and the electrode finger Fe(k+1), a value obtained by dividing a difference between the electrode finger pitch and a section average electrode finger pitch, which is an average of the electrode finger pitch and the electrode finger pitch, by an overall average electrode finger pitch is defined as a pitch deviation ratio, and a distribution obtained by calculating the pitch deviation ratio for all electrode fingers of the IDT electrode or the reflectors is defined as a histogram of the pitch deviation ratio, the IDT electrode or the reflectors have a standard deviation of the pitch deviation ratio in the histogram larger than or equal to about 0.2%.