| 摘要 |
PURPOSE:To reduce the area of electrode and at the same time to improve the separation between tracks, by connecting the fingers to each other for two reed screen type electrodes respectively. CONSTITUTION:When a wave transmitting/receiving electrode T1 is energized, the following waves are generated. That is, a surface acoustic wave P21 going toward a reed screen type electrode T2, a surface acoustic wave P31 going toward a reed screen type electrode T4, and a reflected wave P11 going back to the electrode T1 respectively. When the number N of pairs of electrode fingers of a coupler 10 of surface acoustic wave increases, the wave P21 decreases with increase of the wave P11 respectively. The waves P11, P21, P31 and P41 are equal to each other with N=36, and at the same time the waves P31 and P41 become maximum. A center part 15 between electrodes 11 and 12 is common to both electrodes, and the part 15 can also be separated to be connected electrically. |
