SURFACE ACOUSTIC WAVE DEVICE, ELECTRONIC APPARATUS, AND SENSOR APPARATUS

摘要

A SAW device includes an IDT which is provided on the principal surface of a quartz crystal substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, |ψ|90°×n (where n=0, 1, 2, 3)) and excites a Rayleigh wave (wavelength: λ) in a stopband upper end mode. Inter-electrode-finger grooves are recessed between electrode fingers of the IDT. An IDT line occupancy η and an inter-electrode-finger groove depth G satisfy a predetermined relationship in terms of the wavelength λ, such that the SAW device has a frequency-temperature characteristic of a cubic curve having an inflection point between a maximum value and a minimum value in an operation temperature range. The inflection point is adjustable to a desired temperature or a desired temperature range depending on the IDT line occupancy η within an operation temperature range.

主权项

1. A surface acoustic wave device comprising:
a quartz crystal substrate having Euler angles (−1.5°≦φ≦1.5°, 117°≦θ≦142°, |ψ|≠90°×n (where n=0, 1, 2, 3)); an IDT which has a plurality of electrode fingers in the principal surface of the quartz crystal substrate and excites a Rayleigh wave in a stopband upper endmode, each of the plurality of electrode fingers being separated by a groove having a trapezoidal cross-sectional shape; and a pair of reflectors on opposing sides of the IDT, wherein a frequency-temperature characteristic is expressed by a curve having a maximum value, a minimum value, and an inflection point between the maximum value and the minimum value, and the temperature of the inflection point is adjustable depending on an IDT line occupancy so as to be within a desired operation temperature range.