Disclosed is a filter bank die having a first acoustic wave (AW) filter having a first antenna terminal and a first filter terminal, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter.

A transmit filter circuit includes an input terminal, an output terminal, plural series arm resonators, and a parallel arm resonator. The input terminal receives a transmit signal. The output terminal is electrically connected to an antenna. The plural series arm resonators are electrically connected in series with each other on a line between the input and output terminals. The plural series arm resonators include first and second series arm resonators. The first series arm resonator is closest to the output terminal. The second series arm resonator is second closest to the output terminal. A first end of the parallel arm resonator is electrically connected to a node between the first and second series arm resonators. A reference potential is provided to a second end of the parallel arm resonator. The resonant frequency of the first series arm resonator is higher than that of the second series arm resonator.

When a current flowing in a series circuit including an equivalent resistance, an equivalent inductor, and an equivalent capacitance in an electric equivalent circuit of a specific resonator in each filter is defined as an acoustic path current, under conditions that a phase of an acoustic path current of a first transmission filter at a side of a common terminal at a frequency within a first transmission band is represented as θ1.sub.Tx, a phase of an acoustic path current of the first transmission filter at the side of the common terminal at a frequency within a second transmission band is represented as θ2.sub.Tx, a phase of an acoustic path current of a first reception filter at the side of the common terminal at a frequency within the first transmission band is represented as θ1.sub.Rx, and a phase of an acoustic path current of the first reception filter at the side of the common terminal at a frequency within the second transmission band is represented as θ2.sub.Rx, a multiplexer satisfies a first condition: |(2.Math.θ1.sub.Tx−θ2.sub.Tx)−(2.Math.θ1.sub.Rx−θ2.sub.Rx)|=180°±90°, or a second condition: |(2.Math.θ2.sub.Tx−θ1.sub.Tx)−(2.Math.θ2.sub.Rx−θ1.sub.Rx)|=180°±90°.

An acoustic wave device includes first and second IDT electrodes electrically connected in series with each other by a common busbar common to the first and second IDT electrodes. In each of a first acoustic impedance layer and a second acoustic impedance layer, at least one of at least one high acoustic impedance layer and at least one low acoustic impedance layer is a conductive layer. At least a portion of the conductive layer in the first acoustic impedance layer and at least a portion of the conductive layer in the second acoustic impedance layer do not overlap with the common busbar when viewed in plan from a thickness direction of a piezoelectric layer. The conductive layer in the first acoustic impedance layer and the conductive layer in the second acoustic impedance layer are electrically insulated from each other.

Aspects of this disclosure relate to methods of manufacturing bulk acoustic wave components. Such methods include plasma dicing to singulate individual bulk acoustic wave components. A buffer layer can be formed over a substrate of bulk acoustic wave components such that streets are exposed. The bulk acoustic wave components can be plasma diced along the exposed streets to thereby singulate the bulk acoustic wave components

The present disclosure provides a film piezoelectric acoustic wave filter and a fabrication method. The film piezoelectric acoustic wave filter includes a first substrate; a plurality of acoustic wave resonator units disposed on the first substrate, where each acoustic wave resonator unit includes a piezoelectric induction plate, and a first electrode and a second electrode which are opposite to each other for applying a voltage to the piezoelectric induction plate; and further includes a capping layer on the first substrate, where the capping layer includes a plurality of sub-caps, a sub-cap of the plurality of sub-caps surrounds an acoustic wave resonator unit of the plurality of acoustic wave resonator units to form a first cavity between the acoustic wave resonator unit and the sub-cap, and a separation portion is disposed between adjacent sub-caps to isolate adjacent first cavities.

A ladder filter comprises series arm bulk acoustic wave resonators electrically connected in series between an input port and an output port and shunt bulk acoustic wave resonators electrically connected between adjacent ones of the series arm bulk acoustic wave resonators and ground, each of the arm bulk acoustic resonators including a central active region and a raised frame region outside of the central active region, each of the series arm bulk acoustic resonators including a piezoelectric film, at least one of the series arm bulk acoustic wave resonators including a layer of oxide disposed directly on the piezoelectric film in the raised frame region, and a metal layer disposed directly on the piezoelectric film in the central active region and on the layer of oxide in the raised frame region, the metal layer having a thickness in the raised frame region no greater than in the central active region.

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 method for fabricating bulk acoustic wave resonator with mass adjustment structure, comprising following steps of: forming a sacrificial structure mesa on a substrate; etching the sacrificial structure mesa such that any two adjacent parts have different heights, a top surface of a highest part of the sacrificial structure mesa is coincident with a mesa top extending plane; forming an insulating layer on the sacrificial structure mesa and the substrate; polishing the insulating layer to form a polished surface; forming a bulk acoustic wave resonance structure including a top electrode, a piezoelectric layer and a bottom electrode on the polished surface; etching the sacrificial structure mesa to form a cavity; the insulating layer between the polished surface and the mesa top extending plane forms a frequency tuning structure, the insulating layer between the mesa top extending plane and the cavity forms a mass adjustment structure.

A method of fabricating a configurable single crystal acoustic resonator (SCAR) device integrated circuit. The method includes providing a bulk substrate structure having first and second recessed regions with a support member disposed in between. A thickness of single crystal piezo material is formed overlying the bulk substrate with an exposed backside region configured with the first recessed region and a contact region configured with the second recessed region. A first electrode with a first terminal is formed overlying an upper portion of the piezo material, while a second electrode with a second terminal is formed overlying a lower portion of the piezo material. An acoustic reflector structure and a dielectric layer are formed overlying the resulting bulk structure. The resulting device includes a plurality of single crystal acoustic resonator devices, numbered from (R1) to (RN), where N is an integer greater than 1.