The invention provides a filter device, an RF front-end device and a wireless communication device. The filter device comprises a substrate, at least one resonance device, a passive device and a connector, wherein the at least one resonance device has a first side and a second side opposite to the first side, the substrate is located on the first side, and the passive device is located on the second side. The at least one resonance device is connected to the passive device through the connector. The RF filter device formed by integrating the resonance device (such as an SAW resonance device or a BAW resonance device) and the passive device (such as an IPD) in one die can broaden the passband width, has a high out-of-band rejection, and occupies less space in an RF front-end chip.

A radio frequency module includes a mount board, an acoustic wave filter, a temperature sensor, and a correction circuit. The mount board has a first principal surface and a second principal surface on opposite sides of the mount board. The acoustic wave filter is disposed on the first principal surface side of the mount board. The temperature sensor is disposed on the second principal surface side of the mount board. The correction circuit corrects a pass band of the acoustic wave filter in accordance with a temperature measured by the temperature sensor.

A multiplexer includes a filter located between a common terminal and an individual terminal, and a filter that is located between the common terminal and an individual terminal and that has a pass band whose frequency is lower than the pass band of the filter. The filter includes serial arm resonators provided on the first path connecting the common terminal to the individual terminal. Each of the serial arm resonators includes a piezoelectric substrate and an IDT electrode which use leaky waves as principal acoustic waves. The occurrence frequency of the Rayleigh wave response of the serial arm resonator is different from that of the serial arm resonator.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a multi-layer mass loading strip. The mass loading strip has a density that is higher than a density of the temperature compensation layer. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can include a first layer for adhesion and a second layer for mass loading. The mass loading strip can suppress a transverse mode.

A multiplexer includes first and second filters and additional circuits. The first filter is coupled to transmit and antenna terminals, the second filter is coupled to receive and antenna terminals, one additional circuit is coupled to transmit and receive terminals, and another additional circuit is coupled to transmit and antenna terminals. Pass bands of the first and second filters are respectively first and second frequency bands, and the second frequency band including a center frequency higher than a center frequency of the first frequency band. The one additional circuit includes a first resonator group including first IDT electrodes aligned in a propagation direction of an acoustic wave. The other additional circuit includes a second resonator group including second IDT electrodes aligned in the propagation direction. An average pitch of electrode fingers is greater among the first IDT electrodes than the second IDT electrodes.

A multiplexer (1) includes a plurality of filters connected to a common terminal (110). The multiplexer (1) includes: a low-frequency filter (11L) that is formed of at least one surface acoustic wave resonator arranged between the common terminal (110) and the input/output terminal (120) and has a first pass band; a high-frequency filter (12H) that is connected between the common terminal (110) and the input/output terminal (130) and has a second pass band located at a higher frequency than the first pass band; and a capacitor (C.sub.B1) that is serially arranged in a connection path between the common terminal (110) and the low-frequency filter (11L). The Q value of the capacitor (C.sub.B1) in the second pass band is higher than the Q value in the second pass band of a capacitance obtained by treating the at least one surface acoustic wave resonator of the low-frequency filter (11L) as a capacitance.

An acoustic wave element which can be reduced in size and produced relatively easily, practically used without using harmful substances, and can suppress a surface acoustic wave propagation loss, which has an excellent temperature coefficient of frequency and a velocity dispersion characteristic, and with which an increase in the reflection coefficient of interdigital transducers can be suppressed, and a method for manufacturing the acoustic wave element are provided. The acoustic wave element includes a pair of electrodes provided on both surfaces of a piezoelectric substrate, and a dielectric film provided on a first surface of the piezoelectric substrate so as to cover the electrode. The acoustic wave element alternatively includes interdigital transducers provided on a first surface of the piezoelectric substrate, and a dielectric film provided on the interdigital transducers, a gap between the interdigital transducers, and/or a second surface of the piezoelectric substrate.

The present disclosure relates to acoustic wave devices, and particularly to high quality factor (Q) transducers for surface acoustic wave (SAW) devices. An exemplary SAW device includes an interdigital transducer (IDT) between two reflective gratings to form a resonator. The resonator operates through shear horizontal mode acoustic waves, and therefore suppression of transverse modes (parallel to electrode fingers of the IDT) is desired. A piston mode can be formed in the resonator to suppress transverse modes, which may also increase energy leakage and result in a lower Q. A higher Q is achieved by adding a fast region at an end of one or more of the electrode fingers of the IDT.

An apparatus is disclosed for a surface-acoustic-wave filter with an electrical conductor having a floating potential. In an example aspect, the apparatus includes a surface-acoustic-wave filter with a piezoelectric layer and an electrode structure disposed on a surface of the piezoelectric layer. The electrode structure includes a first comb-shaped structure and a second comb-shaped structure. The electrode structure also includes at least one electrical conductor positioned between the first comb-shaped structure and the second comb-shaped structure such that a gap separates the at least one electrical conductor from the first comb-shaped structure and the second comb-shaped structure.

A stacked AW filter package includes a first substrate stacked on a second substrate. The first substrate has a first AW filter circuit on first surface and a metal layer on a second surface. The second substrate has a second AW filter circuit disposed in a cavity between the metal layer of the first substrate and a third surface of the second substrate. The metal layer is coupled to the second AW filter circuit by a metal interconnect formed in a metallization layer on a side surface of the first substrate. The metal layer provides isolation to reduce cross-talk (e.g., electromagnetic interference) within the stacked AW filter package between the first AW filter circuit and the second AW filter circuit. Including the metal layer in the stacked AW filter package improves signal quality of transmitted and received signals filtered in the first and second AW filter circuits.