| 摘要 |
PURPOSE: A surface acoustic wave device and a method of producing the same are provided to effectively suppress considerable ripples, which are noticeably found in the group delay time characteristic in particular, within the bandpass area. CONSTITUTION: A surface acoustic wave device(1) includes a substantially rectangular piezoelectric substrate(2) made of a quartz substrate or other suitable substrate and at least one inter-digital transducer(IDTs)(3,4) placed on the top of the piezoelectric substrate(2), a pair of reflectors(5,6). The IDT(3) includes a pair of comb-like electrodes(3a,3b), and the IDT(4) includes a pair of comb-like electrodes(4a,4b). The comb-like electrodes(3a,3b,4a,,4b) each include a plurality of electrode fingers, namely,(3a1,3b1,4a1,4b). The plurality of electrode fingers(3a1,3b1,4a1,,4b1) extend substantially parallel to each other. The IDT(3) becomes an input IDT, and an output is taken from the IDT(4). As an input voltage is applied to the IDT(3), surface acoustic waves are excited, and are propagated in a direction that is perpendicular to the direction in which the electrode fingers(3a1,3b1,4a1,4b1) extend. The reflectors(5,6) are provided at both sides of the location where the IDTs(3,4) are positioned in the propagating direction of the surface waves. The reflectors(5,6) preferably made of grating reflectors, each having a plurality of electrode fingers(5a,6a). The plurality of electrode fingers(5a,6a) are each short-circuited at both ends thereof. |
