| 摘要 |
PURPOSE:To reduce the impedance of a titled device without prolonging the length of aperture, by setting the electrode width and the space of a reed screen electrode as specified within a repetitive period and suppressing spurious reflection. CONSTITUTION:The electrode widths 7, 9 of the reed screen electrode are set to 3lambda0/16 (where; lambda0 is the wavelength of a surface acoustic wave) and the spaces 8, 10 are set to lambda0/16, respectively. Further, the repetitive period 11 of the electrode is set equal to the wavelength lambda0 of the surface acoustic wave. Through form mation in such a manner since the spurious reflections 13-16 to be generated are canceled according to the relation of phase, the spurious reflection is suppressed. Further, the electrode widths 7, 9 are increased, the capacitance between the electrodes in increased, thus the reduction in the impedance of the device is attained without increasing the length of the aperture 12. |
