| 摘要 |
PURPOSE:To miniaturize the multi-channel filter, by using a reflected wave reflecting multiplexingly between an output electrode and an input electrode of a surface acoustic wave element. CONSTITUTION:Input interdigital (ID) electrodes 5', 5 and output ID electrodes 6, 6' are provided on a piezoelectric substrate respectively. To generate a reflected wave TTE of a multiplex reflecting wave largely between both the electrodes, the impedance between the output ID terminal and an external circuit is matched and both ID electrodes are formed by using an electrode member having a large mass. The elastic surface wave element thus formed is used as the multi-channel filter, allowing to reduce the distance d1 between both ID electrodes and to reduce the size of the piezoelectric substrate. Thus, the multi- channel filter is miniaturized. |
