摘要:
A surface-acoustic-wave device includes at least first and second surface-acoustic-wave elements formed on a common piezoelectric substrate and cascaded with each other, each of the first and second surface-acoustic-wave elements including a plurality of interdigital electrodes having a plurality of electrode fingers overlapping with each other in correspondence to a path of a surface acoustic wave on the piezoelectric substrate, wherein the width of overlapping of the electrode fingers is changed between the first surface-acoustic-wave element and the second surface-acoustic-wave element.
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:
A surface acoustic wave device includes a piezoelectric substrate of a single crystal LiTaO3 and an electrode pattern provided on the piezoelectric substrate. The electrode pattern contains Al as a primary component and has a thickness in a range of 0.03-0.15 times a wavelength of a surface acoustic wave excited on the piezoelectric substrate. The piezoelectric substrate has an orientation rotated about an X-axis thereof from a Y-axis thereof toward a Z-axis thereof, with a rotational angle of 38-46°.
摘要:
A double-mode surface-acoustic device having a piezoelectric substrate with two reflectors placed on the piezoelectric substrate and first through third interdigital electrodes placed on the substrate consecutively between the two reflectors. Each electrode containing first through third number of pairs of electrode fingers, respectively.
摘要:
A piezoelectric substrate having two reflectors along a propagation path of a surface acoustic wave and three interdigital electrodes provided on said piezoelectric substrate consecutively between the reflectors. A primary side electrode is connected to an input/output terminal and a secondary side electrode is connected to a second input/output terminal. Each interdigital electrode includes include pairs of electrode fingers, where the pair of electrodes for one interdigital electrode is different than a pair of electrodes for another interdigital electrode.
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:
A surface acoustic wave device includes a piezoelectric substrate of a single crystal LiTaO.sub.3 and an electrode pattern provided on the piezoelectric substrate. The electrode pattern contains Al as a primary component and has a thickness in a range of 0.03-0.15 times a wavelength of a surface acoustic wave excited on the piezoelectric substrate. The piezoelectric substrate has an orientation rotated about an X-axis thereof from a Y-axis thereof toward a Z-axis thereof, with a rotational angle of 39-46.degree..
摘要:
A surface acoustic wave device supported by a package body. At least one surface acoustic wave element having interdigital electrodes disposed on a propagation path of a surface acoustic wave on the piezoelectric substrate. These interdigital electrodes include an input-side interdigital electrode connected to a ground pad on the package body and an output-side interdigital electrode connected to another ground pad on the package body.
摘要:
A surface acoustic wave device includes a piezoelectric substrate having a first surface on which comb-like electrodes, first pads connected thereto, and a first film are provided. The first film is located so as to surround the comb-like electrodes. A base substrate has a second surface on which second pads joined to the first pads and a second film joined to the first film are provided. The first and second films joined by a surface activation process define a cavity in which the comb-like electrodes and the first and second pads are hermetically sealed.
摘要:
A surface acoustic wave filter capable of obtaining a low insertion loss and wide bandwidth characteristic is provided. The surface acoustic wave filter includes a piezoelectric substrate; a pair of reflective electrodes formed on the piezoelectric substrate; and a plurality of comb electrodes formed between the pair of reflective electrodes on the piezoelectric substrate, wherein, in regard to the neighboring two comb electrodes among the plurality of comb electrodes, an electrode pitch of one comb electrode is set so that continuously varying phases of surface acoustic waves respectively generated by the two comb electrodes are obtained in a gap opposite to an outermost finger electrode of the other neighboring comb electrode.