A Lamb wave resonator includes a piezoelectric material layer, a first finger electrode, a second finger electrode, at least two floating electrodes, and at least two gaps. The first finger electrode is disposed on one side of the piezoelectric material layer and includes a first main portion and first fingers. The second finger electrode is disposed on the side of the piezoelectric material layer and includes a second main portion and second fingers. The first fingers are parallel to and alternately arranged with the second fingers. The floating electrodes are disposed between each first finger and each second finger, and the gaps are disposed at two ends of each floating electrode, respectively.

An electro acoustic resonator is provided. The resonator has a gap short structure (GSS) to electrically short at least an area of the transversal gap to suppress transversal gap mode excitations. The gap short structure may be provided by a conductive stripe in the gap and parallel to or inclined with respect to the bus bar (BB) shorting adjacent IDT fingers. Additional connectors between the stripe and the bus bar may be provided. The connectors may have different pitch or metallization ratio with respect to the ID fingers. The connectors may be offset from the position of the fingers and my be inclined with respect to the bus bars. Multiple parallel stripes in the gap may provide a transversal reflector. By using a gap short structure a further improved transversal mode suppression of piston mode designs can be achieved.

An acoustic wave filter includes at least one serial arm resonance circuit on a path connecting input/output terminals, and at least one parallel arm resonance circuit between a node on the path and a ground, in which each of the at least one serial arm resonance circuit and the at least one parallel arm resonance circuit includes an acoustic wave resonator, a first parallel arm resonance circuit of the at least one parallel arm resonance circuit includes a bridging capacitor connected in parallel to the acoustic wave resonator, an anti-resonant frequency of the first parallel arm resonance circuit is positioned on a higher-frequency side than the pass band, and a resonant frequency of a first serial arm resonance circuit of the at least one serial arm resonance circuit is positioned on a lower-frequency side than the anti-resonant frequency of the first parallel arm resonance circuit.

An acoustic wave filter includes series arm resonators and parallel arm resonators, which are acoustic wave resonators including IDT electrodes provided on a piezoelectric substrate. The IDT electrodes of the series arm resonators include a first thinned electrode (floating electrode) and the IDT electrodes of the parallel arm resonators include a second thinned electrode (filled electrode).

An acoustic wave filter includes series arm resonators and parallel arm resonators, which are acoustic wave resonators including IDT electrodes provided on a piezoelectric substrate. The IDT electrodes of the series arm resonators include a first thinned electrode (floating electrode) and the IDT electrodes of the parallel arm resonators include a second thinned electrode (filled electrode).

A multiplexer includes a transmission-side filter electrically connected to a common terminal and a transmission input terminal, and a transmission-side filter electrically connected to the common terminal and a transmission input terminal. The transmission-side filter includes a plurality of series arm resonators and a plurality of parallel arm resonators. Capacitance elements are respectively electrically connected in parallel to the series arm resonator and the parallel arm resonator, which are connected most proximately to the common terminal. IDT electrodes of a series arm resonator and a parallel arm resonator connected most proximately to the common terminal do not include a thinning electrode, and others of the series arm resonators and the parallel arm resonators include thinning electrodes.

An acoustic wave filter includes series arm resonators each including an IDT electrode on a piezoelectric substrate. Resonant frequencies of the series arm resonators are positioned within the pass band of the acoustic wave filter. The IDT electrode includes a pair of comb-shaped electrodes. Each of the comb-shaped electrodes includes electrode fingers and a busbar electrode. The electrode fingers extend in a direction intersecting a propagation direction of acoustic waves and are parallel with each other. One end of an electrode finger and one end of another electrode finger are connected with each other by the busbar electrode. The IDT electrode of the series arm resonator with the lowest anti-resonant frequency includes two or more withdrawal-weighted floating electrodes without any of the electrode fingers of one of the comb-shaped electrodes interposed therebetween.

In an acoustic wave device, a piezoelectric body is directly or indirectly provided on a high acoustic velocity material layer, an interdigital transducer electrode is directly or indirectly provided on the piezoelectric body, the interdigital transducer electrode includes a first busbar, a second busbar spaced away from the first busbar, a plurality of first electrode fingers, and a plurality of second electrode fingers, and a weighting is applied to the interdigital transducer electrode by providing a floating electrode finger not electrically connected to the first busbar or the second busbar or applied by providing an electrode finger formed by metallizing a gap between the first electrode fingers or a gap between the second electrode fingers to integrate the first electrode fingers or the second electrode fingers.

An acoustic wave filter includes at least one serial arm resonance circuit on a path connecting input/output terminals, and at least one parallel arm resonance circuit between a node on the path and a ground, in which each of the at least one serial arm resonance circuit and the at least one parallel arm resonance circuit includes an acoustic wave resonator, a first parallel arm resonance circuit of the at least one parallel arm resonance circuit includes a bridging capacitor connected in parallel to the acoustic wave resonator, an anti-resonant frequency of the first parallel arm resonance circuit is positioned on a higher-frequency side than the pass band, and a resonant frequency of a first serial arm resonance circuit of the at least one serial arm resonance circuit is positioned on a lower-frequency side than the anti-resonant frequency of the first parallel arm resonance circuit.

An electro acoustic resonator is provided. The resonator has a gap short structure (GSS) to electrically short at least an area of the transversal gap to suppress transversal gap mode excitations. The gap short structure may be provided by a conductive stripe in the gap and parallel to or inclined with respect to the bus bar (BB) shorting adjacent IDT fingers. Additional connectors between the stripe and the bus bar may be provided. The connectors may have different pitch or metallization ratio with respect to the ID fingers. The connectors may be offset from the position of the fingers and my be inclined with respect to the bus bars. Multiple parallel stripes in the gap may provide a transversal reflector. By using a gap short structure a further improved transversal mode suppression of piston mode designs can be achieved.