An acoustic wave device includes a piezoelectric layer, a pair of comb-shaped electrodes disposed on a first surface of the piezoelectric layer, each of the pair of comb-shaped electrodes including electrode fingers that excite an acoustic wave, a support substrate disposed at a second surface side of the piezoelectric layer, and having protruding portions and/or recessed portions on a first surface, which is closer to the piezoelectric layer, of the support substrate, each of the protruding portions and/or the recessed portions having a shape in which each of left and right side surfaces has linear slopes inclined at different angles with respect to the first surface of the piezoelectric layer in a cross-sectional view, and a second insulating layer located between the piezoelectric layer and the support substrate and disposed on the third surface, on which the protruding portions and/or the recessed portions are formed, of the support substrate.

A ladder-type filter includes a support substrate, a piezoelectric layer provided on the support substrate, a parallel resonator including first electrode fingers provided on the piezoelectric layer and having a first average pitch and a first average duty ratio, a largest first average pitch being equal to or greater than two times a thickness of the piezoelectric layer, a first end of the parallel resonator being coupled to a path between input and output terminals, a second end of the parallel resonator being coupled to a ground, and a series resonator connected in series between the input and output terminals, the series resonator including second electrode fingers provided on the piezoelectric layer and having a second average pitch and a second average duty ratio, a second average duty ratio in at least one series resonator being less than a smallest first average duty ratio.

A ladder-type filter includes a support substrate, a piezoelectric layer provided on the support substrate, a parallel resonator including first electrode fingers provided on the piezoelectric layer and having a first average pitch and a first average duty ratio, a largest first average pitch being equal to or greater than two times a thickness of the piezoelectric layer, a first end of the parallel resonator being coupled to a path between input and output terminals, a second end of the parallel resonator being coupled to a ground, and a series resonator connected in series between the input and output terminals, the series resonator including second electrode fingers provided on the piezoelectric layer and having a second average pitch and a second average duty ratio, a second average duty ratio in at least one series resonator being less than a smallest first average duty ratio.

RF filtering circuitry comprises a first node, a second node, and a series signal path between the first node and the second node. A number of acoustic resonators are coupled to one or more of the first node and the second node via the series signal path. A first one of the acoustic resonators is associated with a first quality factor and a first electromechanical coupling coefficient. A second one of the acoustic resonators is associated with a second quality factor and a second electromechanical coupling coefficient. The first quality factor is different from the second quality factor and the first electromechanical coupling coefficient is different from the second electromechanical coupling coefficient.

A filter includes a series resonator including a first piezoelectric layer and first electrodes, and a parallel resonator including a second piezoelectric layer and second electrodes. Each of the first and second piezoelectric layers is a monocrystalline lithium niobate layers, has an X-axis orientation in a planar direction, and has a thickness direction in a direction obtained by a 105° rotation of a +Z-axis orientation toward a +Y-axis orientation. The first electrodes face each other across the first piezoelectric layer to form a first resonance region and are extracted from the first resonance region in a direction substantially parallel to the X-axis orientation of the first piezoelectric layer. The second electrodes face each other across the second piezoelectric layer to form a second resonance region and are extracted from the second resonance region in a direction substantially orthogonal to the X-axis orientation of the second piezoelectric layer.

A method of plugging a hydrocarbon well includes deploying a downhole tool to remove at least a portion of a casing at a section of well to be plugged. Deploying a blocking device downhole to block a bottom of the section of well to be plugged. Deploying a plugging material downhole onto the blocking device to fill an area to be plugged. Deploying an exothermic fluid downhole, wherein activation of the exothermic material liquefies the plugging material. Allowing the plugging material and the exothermic fluid to solidify form a cast-in-place plug that fills the section of well to be plugged.

A resonator, a filter and a duplexer, which relate to the technical field of resonators. The resonator includes: a substrate, and a lower electrode layer, a piezoelectric layer and an upper electrode layer, which are sequentially formed on the substrate, wherein an acoustic reflection structure is formed on a surface of the substrate that is close to the lower electrode layer, and an overlapping region of the acoustic reflection structure, the lower electrode layer, the piezoelectric layer and the upper electrode layer along a stacking direction forms a resonant region; and in the resonant region, the surface, which is away from the substrate, of at least one of the lower electrode layer, the piezoelectric layer and the upper electrode layer is etched to form an etched region, the depth of the etched region is less than the thickness of an etched layer, and the area of the etched region is less than the area of the resonant region. By means of controlling an etching area ratio of the resonant region to the etched region, the resonator can obtain a plurality of different resonant frequencies on the same wafer without increasing processes.

A multiplexer includes a first filter located between a common terminal and a first terminal to pass a signal in a first passband, and a second filter located between the common terminal and a second terminal to pass a signal in a second passband. A first series arm circuit included in the first filter includes a first series arm resonator and a second series arm resonator. The first series arm circuit is connected to the common terminal not through a circuit including an elastic wave resonator and a connecting point of the circuit. The first series arm circuit has a first antiresonance frequency and a second antiresonance frequency higher than the first antiresonance frequency. The second antiresonance frequency is higher than a higher edge of the first passband. The first antiresonance frequency is at or lower than a higher edge of the second passband.

A multiplexer includes a first filter located between a common terminal and a first terminal to pass a signal in a first passband, and a second filter located between the common terminal and a second terminal to pass a signal in a second passband. A first series arm circuit included in the first filter includes a first series arm resonator and a second series arm resonator. The first series arm circuit is connected to the common terminal not through a circuit including an elastic wave resonator and a connecting point of the circuit. The first series arm circuit has a first antiresonance frequency and a second antiresonance frequency higher than the first antiresonance frequency. The second antiresonance frequency is higher than a higher edge of the first passband. The first antiresonance frequency is at or lower than a higher edge of the second passband.

A filter device includes a filter circuit including series-arm resonators and series-arm-resonator connecting wires, and an additional circuit including a resonator including first and second interdigital transducer electrodes, first and second capacitors connected between the first and second interdigital transducer electrodes and the filter circuit, and first and second I-C connecting wires connected to the first and second interdigital transducer electrodes and the first and second capacitors, the additional circuit being connected in parallel with a portion of the series-arm resonators in the filter circuit. The first and second interdigital transducer electrodes are output-side interdigital transducer electrodes. A capacitance of the first capacitor is smaller than the capacitance of the second capacitor. A shortest distance among distances between the first I-C connecting wire and the series-arm-resonator connecting wires is shortest among shortest distances between the I-C connecting wires and the series-arm-resonator connecting wires.