Surface acoustic wave filter device on 40.degree. to 42.degree. rotated
Y-X LITAO.sub.3
    3.
    发明授权
    Surface acoustic wave filter device on 40.degree. to 42.degree. rotated Y-X LITAO.sub.3 失效
    表面声波滤波器装置在40°〜42°旋转Y-X LITAO3

    公开(公告)号:US5874869A

    公开(公告)日:1999-02-23

    申请号:US925732

    申请日:1997-09-09

    摘要: A surface acoustic wave device includes a piezoelectric substrate of a LiTaO.sub.3 single crystal, the crystal having X, Y and Z axes and a cut plane. The X axis of the crystal is oriented in a direction of propagation of surface acoustic waves. The cut plane of the crystal is rotated around the X axis at a rotated angle from the Y axis to the Z axis, the rotated angle being in a range between 40.degree. and 42.degree.. A pair of reflectors are formed on the substrate and aligned in a row in the direction of propagation. Interdigital transducers are formed on the substrate and aligned in the row in the direction of propagation, the interdigital transducers interposed between the reflectors, each interdigital transducer having pairs of mutually opposed primary electrode fingers and secondary electrode fingers, the interdigital transducers including at least a front transducer, a middle transducer and a rear transducer aligned in the row in the direction of propagation. In the device, a ratio of the number of pairs of the electrode fingers in one of the front transducer and the rear transducer to the number of pairs of the electrode fingers in the middle transducer is in a range between 55% and 80%.

    摘要翻译: 表面声波装置包括LiTaO3单晶的压电基片,具有X,Y和Z轴的晶体和切割平面。 晶体的X轴在表面声波的传播方向上取向。 晶体的切割面以X轴旋转,从Y轴向Z轴旋转,旋转角度在40°〜42°的范围内。 一对反射器形成在基板上并沿着传播方向成一排排列。 叉指换能器形成在基板上并沿着传播方向排列成行,插入在反射器之间的叉指换能器,每个叉指换能器具有成对的相互对置的主电极指和辅助电极指,叉指换能器至少包括前部 传感器,中间传感器和后传感器在传播方向上排成一行。 在该装置中,前换能器和后换能器中的一个中的电极指的对数与中间换能器中的电极指对数的比率在55%至80%的范围内。

    Surface acoustic wave device
    7.
    发明授权
    Surface acoustic wave device 失效
    表面声波装置

    公开(公告)号:US06483402B2

    公开(公告)日:2002-11-19

    申请号:US09748115

    申请日:2000-12-27

    IPC分类号: H03H964

    摘要: The present invention provides a surface acoustic wave filter having an unbalance-to-balance conversion function and an impedance conversion function. This surface acoustic wave filter includes a piezoelectric substrate, a first surface acoustic wave filter that is made up of input and output interdigital transducers (IDTs), and a second surface acoustic wave filter that is also made up of input and output IDTs. The phase difference between the first surface acoustic wave filter and the second surface acoustic wave filter is approximately 180°. The input IDT of the first surface acoustic wave filter is connected to the input IDT of the second surface acoustic wave filter by a connecting wire, and a terminal extending from this connecting wire serves as an unbalanced terminal. An output terminal extends from the output IDTs of the first surface acoustic wave filter that are not connected to the second surface acoustic wave filter, and another output terminal extends from the output IDTS of the second surface acoustic wave filter that are not connected to the first surface acoustic wave filter. These output terminals constitute a balanced terminal 35.

    摘要翻译: 本发明提供一种具有不平衡平衡转换功能和阻抗转换功能的表面声波滤波器。 该表面声波滤波器包括压电基板,由输入和输出叉指式换能器(IDT)构成的第一声表面波滤波器,以及也由输入和输出IDT组成的第二声表面波滤波器。 第一声​​表面波滤波器和第二声表面波滤波器之间的相位差约为180°。 第一声​​表面波滤波器的输入IDT通过连接线连接到第二声表面波滤波器的输入IDT,从该连接线延伸的端子作为不平衡端子。 输出端子从未连接到第二声表面波滤波器的第一表面声波滤波器的输出IDT延伸,另一个输出端从第二声表面波滤波器的未连接到第一声表面波滤波器的输出IDTS延伸, 表面声波滤波器。 这些输出端子构成平衡端子35。