| 摘要 |
PURPOSE: To allow a device to have a small insertion loss and an excellent phase and frequency characteristic by arranging electrodes to obtain a natural single phase unidirectional transducer characteristic together with anisotropy of a substrate onto the substrate whose cut and propagation direction is selected so that an Euler's angle (ψγ,ϕ) is a specific angular range. CONSTITUTION: A regular electrode ofλ/4 is provided as a sender side transducer 12 is provided to a lithium tetraborate substrate 11 cut by an Euler's angle such as (0 deg., 51 deg., 90 deg.) and a SAW filter provided with a receiver side transducer 13 such as 10 pairs of double electrodes is formed. After an aluminum film 0.37μm thick is uniformly depositted to the surface of the lithium tetraborate substrate 11 cut by the angle of (0<0> , 51<0> ,90<0> ), the transducers 12, 13 are formed by using a photo lithographic technology. The transducer 12 is made up of electrodes having a regular interdigital structure, positive and negative electrodes 12a, 12b with an electrode width ofλ/4 are arranged and the transducer 13 is formed by positive negative electrodes 13a, 13b. Then the electrodes of natural single phase unidirectional transducer characteristic is obtained with the anisotropy of the substrate.
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