PURPOSE: To make frequency-temperature characteristics coincident with one another among plural resonance frequencies, by setting the ratio of the width of electrode fingers to the width of no-electrode parts between electrodes to a desired value.
CONSTITUTION: Three bus bar electrodes 2, 3, and 4 are provided in the X-axial direction on the main surface of an ST cut quartz substrate 1, and the center bus bar electrode 3 is used as a common electrode for both resonators to excite two kinds of resonance frequency. When resonance frequencies, surface wave wavelengths, widths of electrode fingers, and widths of no-electrode parts of respective resonators and the thickness of electrode films are denoted as f1 and f2, λ1 and λ2, l1 and l2, s1 and s2, and (h) respectively, both resonators show the same peak temperature on condition that l2/l1=(λ2/λ1)2=(f1/f2)2 is true. Consequently, the frequency f1 of the resonator as a reference is determined, and the quartz cut angle and the electrode finger width l1 are so determined that the peak temperature of frequency-temperature characteristics becomes a prescribed value, and thus, the electrode finger width l2 of the resonator having the frequency f2 is obtained automatically.
TANAKA MASAKI
ONO KAZUO
