| 摘要 |
PURPOSE:To obtain an elastic surface wave device which can suppress the mechanical reflected waves by setting the width of the electrode finger of the inter-digital electrode to about 1/8 wavelength lambda0 of the surface wave at the maximum response frequency and also setting the space to about lambda0/8 between the adjacent electrode fingers featuring the different polarities. CONSTITUTION:Length L at overlap part 33 of upper and lower electrode fingers 31 and 32 is set to be proportional to amplitude A of each peak, and at the same time the center of the space between fingers 31 and 32 is set to coincide with the position of each peak. And width w of each electrode finger is set to w=v/8f0=lambda0/8 (v: sound speed of surface wave; lambda0: wavelength of surface wave) when the frequency is defined as f0 near the maximum response of the inter-digital electrode, and also the space is set to w between the adjacent electrode fingers of different polarities. In such constitution, the reflected waves can be offset mutually between edges A and C, B and D, A' and C' and B' and D' each of the electrode fingers. In other words, the reflected wave can be offset mutually between adjacent electrode fingers of different polarities. |
