An acoustic wave resonator includes a resonating part disposed on and spaced apart from a substrate by a cavity, the resonating part including a membrane layer, a first electrode, a piezoelectric layer, and a second electrode that are sequentially stacked. 0 Å≤ΔMg≤170 Å may be satisfied, ΔMg being a difference between a maximum thickness and a minimum thickness of the membrane layer disposed in the cavity.

An electronic device includes a pop-up device configured to be inserted into a main body of the electronic device in an inserted state, including a gas sensor including a sensor block for sensing a gas, and configured to expose the sensor block to an outer portion of the electronic device in a pop-up state; a power supplier arranged on an outer portion of the pop-up device, configured to supply electric power to the gas sensor; and a connection controller configured to control a connection state of the pop-up device, to block supply of electric power to the gas sensor when the pop-up device is in the inserted state and to supply electric power to the gas sensor when the pop-up device is in the pop-up state, including one or more terminals formed on the pop-up device that move together with the pop-up device when the pop-up device moves.

Aspects of this disclosure relate to a multiplexer with a hybrid acoustic passive filter. The multiplexer includes a plurality of filters configured to filter respective radio frequency signals, a shared filter coupled between each of the plurality of filters and a common node, and a radio frequency filter coupled to the common node. At least a first filter of the plurality of filters includes acoustic resonators and a non-acoustic passive component. Related multiplexers, wireless communication devices, and methods are disclosed.

One example includes an acoustic resonator filter system. The system includes a filter element arranged between a low-voltage rail and a filter-path node through which an RF input signal propagates to provide a filtered RF output signal. The filter element includes an acoustic resonator and a capacitive network arranged in parallel with the acoustic resonator.

A bulk-acoustic wave resonator includes a resonator, including a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate; and an insertion layer disposed below the piezoelectric layer, and configured to partially elevate the piezoelectric layer and the second electrode, wherein the insertion layer may be formed of a material containing silicon (Si), oxygen (O), and nitrogen (N).

Aspects of this disclosure relate to an acoustic wave filter configured to filter a radio frequency signal and a loop circuit coupled to the acoustic wave filter. The loop circuit is configured to generate an anti-phase signal to a target signal at a particular frequency. The loop circuit includes a Lamb wave element. Related radio frequency modules and wireless communication devices are disclosed.

An acoustic wave device includes a piezoelectric substrate including a crystal axis and an IDT electrode. When an acoustic wave propagation direction is a first direction and a direction perpendicular to the first direction is a second direction, the crystal axis of the piezoelectric substrate is inclined toward the second direction with respect to the thickness direction. The IDT electrode includes first and second electrode fingers interdigitated with each other. The portion where the first and second electrode fingers overlap in the first direction is a crossing region. The crossing region includes a center region that is centrally located in the second direction and first and second low-acoustic-velocity regions that are located on both sides of the center region in the second direction and in which the acoustic velocity is lower than the acoustic velocity in the center region. The first and second low-acoustic-velocity regions are asymmetrical.

Multiplexers are disclosed. A multiplexer can include a first filter and a second filter that are coupled to a common node. The second filter can include a first type of acoustic wave resonators (e.g., bulk acoustic wave resonators) and a series acoustic wave resonator of a second type (e.g., a surface acoustic wave resonator) that is coupled between the acoustic wave resonators of the first type and the common node. The first filter can provide a single-ended radio frequency signal. In certain embodiments, the first filter can be a receive filter and the second filter can be a transmit filter.

Techniques are disclosed for forming integrated circuit film bulk acoustic resonator (FBAR) devices having multiple resonator thicknesses on a common substrate. A piezoelectric stack is formed in an STI trench and overgrown onto the STI material. In some cases, the piezoelectric stack can include epitaxially grown AlN. In some cases, the piezoelectric stack can include single crystal (epitaxial) AlN in combination with polycrystalline (e.g., sputtered) AlN. The piezoelectric stack thus forms a central portion having a first resonator thickness and end wings extending from the central portion and having a different resonator thickness. Each wing may also have different thicknesses from one another. Thus, multiple resonator thicknesses can be achieved on a common substrate, and hence, multiple resonant frequencies on that same substrate. The end wings can have metal electrodes formed thereon, and the central portion can have a plurality of IDT electrodes patterned thereon.

Aspects of this disclosure relate to hybrid acoustic LC filter with harmonic suppression. The hybrid acoustic LC filter includes a hybrid passive/acoustic and a non-acoustic LC filter cascaded with the hybrid passive/acoustic filter. The hybrid passive/acoustic filter can be configured to filter a radio frequency signal. The hybrid passive/acoustic filter can include acoustic resonators and a non-acoustic passive component. The non-acoustic LC filter can be configured to suppress a harmonic of the radio frequency signal. The non-acoustic LC filter can be a low pass filter or a harmonic notch filter, for example. Related multiplexers, wireless communication devices, and methods are disclosed.