US 12,255,602 B2
Filter and multiplexer
Mamoru Ishida, Tokyo (JP)
Assigned to TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed by TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed on Jul. 14, 2022, as Appl. No. 17/864,927.
Claims priority of application No. 2021-122250 (JP), filed on Jul. 27, 2021; and application No. 2022-107848 (JP), filed on Jul. 4, 2022.
Prior Publication US 2023/0029646 A1, Feb. 2, 2023
Int. Cl. H03H 9/02 (2006.01); H03H 9/13 (2006.01); H03H 9/17 (2006.01); H03H 9/56 (2006.01); H03H 9/70 (2006.01)
CPC H03H 9/02015 (2013.01) [H03H 9/13 (2013.01); H03H 9/17 (2013.01); H03H 9/568 (2013.01); H03H 9/703 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A filter comprising:
a substrate;
a series resonator that is disposed on the substrate, is connected in series between an input terminal and an output terminal, and includes a first piezoelectric layer and a pair of first electrodes, the first piezoelectric layer being a monocrystalline lithium niobate layer or a monocrystalline lithium tantalate layer, an X-axis orientation of crystal orientations of the first piezoelectric layer corresponding to a planar direction, a thickness direction of the first piezoelectric layer corresponding to a direction obtained by rotating a +Z-axis orientation of the crystal orientations of the first piezoelectric layer substantially 105° toward the +Y-axis orientation, the pair of first electrodes being opposite to each other across the first piezoelectric layer to form a first resonance region, each of the pair of first electrodes being extracted from the first resonance region in a direction that is substantially parallel to the X-axis orientation of the crystal orientations of the first piezoelectric layer; and
a parallel resonator that is disposed on the substrate, is connected in parallel between the input terminal and the output terminal, and includes a second piezoelectric layer and a pair of second electrodes, the second piezoelectric layer being a monocrystalline lithium niobate layer or a monocrystalline lithium tantalate layer, an X-axis orientation of crystal orientations of the second piezoelectric layer corresponding to a planar direction, a thickness direction of the second piezoelectric layer corresponding to a direction obtained by rotating a +Z-axis orientation of the crystal orientations of the second piezoelectric layer substantially 105° toward a +Y-axis orientation of the crystal orientations of the second piezoelectric layer, the pair of second electrodes being opposite to each other across the second piezoelectric layer to form a second resonance region, each of the pair of second electrodes being extracted from the second resonance region in a direction that is substantially orthogonal to the X-axis orientation of the crystal orientations of the second piezoelectric layer.