Embodiments may relate to a die such as an acoustic wave resonator (AWR) die. The die may include a first filter and a second filter in the die body. The die may further include an electromagnetic interference (EMI) structure that surrounds at least one of the filters. Other embodiments may be described or claimed.

A surface acoustic wave wafer-level package includes a substrate, an interdigital transducer (IDT) electrode formed on the substrate, a connection electrode electrically connected to the IDT electrode, a side wall formed on the substrate and outside the IDT electrode, a cover formed above the side wall and the IDT electrode to form a cavity, together with the side wall, on the IDT electrode, a connection terminal electrically connected to the connection electrode and protruding above the cover, a first reinforcement layer formed on the cover to at least partially overlap the cavity in a vertical direction, a second reinforcement layer formed to cover the cover and the first reinforcement layer and having holes formed in a portion corresponding to the connection terminal and a portion corresponding to the first reinforcement layer, and bumps formed in the respective holes of the second reinforcement layer to protrude above the second reinforcement layer.

An acoustic wave filter component can include an acoustic wave device including a multi-layer piezoelectric substrate. The multi-layer piezoelectric substrate can include at least a support substrate and a piezoelectric layer. The acoustic wave device can include an interdigital transducer electrode on the piezoelectric layer. An additional layer can be located over the interdigital transducer electrode. The acoustic wave filter component can also include a bulk acoustic wave resonator supported by the additional layer. The acoustic wave device can be a boundary wave resonator, and one or more boundary wave resonators may be provided in a stacked arrangement, with the bulk acoustic wave resonator in the top layer of the stacked arrangement. The acoustic wave device can also be a temperature-compensated surface acoustic wave device.

A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a first solid acoustic mirror, a second solid acoustic mirror, a piezoelectric layer that is positioned between the first solid acoustic mirror and the second solid acoustic mirror, an interdigital transducer electrode on the piezoelectric layer, and a support substrate arranged to dissipate heat associated with the bulk acoustic wave. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the bulk acoustic wave. The first solid acoustic mirror is positioned on the support substrate.

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.

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.

A microelectromechanical resonator device has: a main body, with a first surface and a second surface, opposite to one another along a vertical axis, and made of a first layer and a second layer, arranged on the first layer; a cap, having a respective first surface and a respective second surface, opposite to one another along the vertical axis, and coupled to the main body by bonding elements; and a piezoelectric resonator structure formed by: a mobile element, constituted by a resonator portion of the first layer, suspended in cantilever fashion with respect to an internal cavity provided in the second layer and moreover, on the opposite side, with respect to a housing cavity provided in the cap; a region of piezoelectric material, arranged on the mobile element on the first surface of the main body; and a top electrode, arranged on the region of piezoelectric material, the mobile element constituting a bottom electrode of the piezoelectric resonator structure.

A resonator device may include a stacked first resonator and second resonator. The first resonator may be configured to resonate at a first operating frequency, and the second resonator may be configured to resonate at a second operating frequency different from the first operating frequency. The first resonator may include a first electrode and a first active layer arranged over the first electrode. The second resonator may include a second active layer arranged over the first active layer, and a second electrode arranged over the second active layer. The stacked first resonator and second resonator may be coupled to a reconfiguration switch for selectively operating at the first operating frequency or the second operating frequency. One of the first resonator and the second resonator is active upon selection by the reconfiguration switch, while the other resonator is inactive.

A MEMS (microelectromechanical system) resonator with a material layer of single-crystalline silicon, at least one layer made of material with low thermal diffusivity to reduce thermoelastic dissipations in the MEMS resonator, a layer of piezoelectric material, and a layer made of electrically conducting material. The said-layer with low thermal diffusivity is between the single-crystalline silicon layer and the piezoelectric layer, or between the piezoelectric layer and the electrically conducting layer. The use of a material layer of low thermal diffusivity.

The invention combines two filter technologies on a single device using the same substrate there for. On this substrate a filter circuit is arranged that has a ladder-type or a lattice arrangement of series and parallel impedance elements to provide a hybrid filter having for example a band pass function. The impedance elements are chosen from BAW resonators and LC elements.