| 摘要 |
PURPOSE: To obtain a surface acoustic wave element having unidirectivity without thinning electrode digits by combining split electrodes and single electrodes at prescribed inter-electrode distances to form interdigital electrodes. CONSTITUTION: The electrode digits of interdigital electrodes 121, 122 formed on a piezoelectric base 101 consist of the combinations of split electrodes and single electrodes, the electrode digits of the split electrodes are directly connected to bus bars 113, 114 and the electrode digits of the split electrodes are directly connected to bus bars 111, 112. Distances between the electrode digits of the split electrode and the single electrode are combined as a narrow shape on one side and as a wide shape on the other side. When the wavelength of center frequency of a surface acoustic wave excited from the interdigital electrode on the base 101 is defined as λ, the width of an electrode digit is λ/6, a distance between the electrode digits of a split electrode and a single electrode on one side is λ/4, a distance between both the electrodes on the other side is narrowed, and a distance between the electrode digits of the split electrode is widened, so that the center of excitation is deviated from the center of reflection and unidirectivity can be obtained. |
