A filter includes: one or more series resonators that are connected in series between an input terminal and an output terminal; one or more parallel resonators that are connected in parallel between the input terminal and the output terminal; and a laterally coupled resonator that is connected in parallel with at least one of the one or more series resonators.

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.

A bulk acoustic wave resonator (BAWR) includes a bulk acoustic resonance unit and at least one compensation layer. The bulk acoustic resonance unit includes a first electrode, a second electrode, and a piezoelectric layer disposed between the first electrode and the second electrode. The first electrode, the second electrode, and the piezoelectric layer each include a material that modifies a resonance frequency based on a temperature, and the at least one compensation layer includes a material that adjusts the resonance frequency modified based on the temperature in a direction opposite to a direction of the modification.

A filter using bulk acoustic wave resonators (BAWRs) is provided including BAWRs connected in series or in parallel to each other. A BAWR set is configured by connecting an inductance and capacitance (L/C) element to each BAWR in series or in parallel.

A filter using bulk acoustic wave resonators (BAWRs) is provided including BAWRs connected in series or in parallel to each other. A BAWR set is configured by connecting an inductance and capacitance (L/C) element to each BAWR in series or in parallel.

A Bulk Acoustic Wave (BAW) resonator with an electrically isolated Border (BO) ring is provided. One BAW resonator includes a bottom electrode and a piezoelectric layer over the bottom electrode and having a top surface with a first portion and second portion about the first portion. The BAW resonator also includes a top electrode over the first portion of the piezoelectric layer and a BO ring including a non-conductive portion that is over the second portion of the piezoelectric layer and adjacent to the piezoelectric layer. The BAW resonator may be a Solidly Mounted BAW (SMR-BAW) resonator or a Film BAW Resonator (FBAR). A radio frequency filter including a ladder configuration with the above BAW resonator as a series BAW resonator and methods for fabricating the above BAW resonator are also provided.

An acoustic wave device includes a substrate, first and second resonators above the substrate, and an energy confinement portion. The first resonator includes a first piezoelectric film including a first main surface facing a second main surface, both having anisotropy. First and second electrodes are provided on the first or second main surface. The second resonator includes a second piezoelectric film including a third main surface facing a fourth main surface, both having anisotropy. Third and fourth electrodes are provided on the third or fourth main surface. In the first resonator, a first excitation portion is where the first and second electrodes overlap or where the first electrode faces the second electrode. In the second resonator, a second excitation portion is where the third and fourth electrodes overlap or where the third electrode faces the fourth electrode. The first and second excitation portions have shapes including length directions that differ.

A filter device includes a first filter including a first input terminal, a first output terminal, a first series arm including first series arm resonators, and first parallel arms connected to the first series arm and each including a first parallel arm resonator, the first filter having a pass band in a predetermined frequency band, a second filter including a second input terminal, a second output terminal, a second series arm including second series arm resonators, and second parallel arms connected to the second series arm and each including a second parallel arm resonator, the second filter having a pass band in the predetermined frequency band, a substrate including the first and second filters, and an inductor connected between a ground terminal and a parallel arm resonator included in at least one parallel arm of the first and second parallel arms.

A coupled resonator filter device is disclosed. The coupled resonator filter device includes a substrate with one or more acoustic reflector layers disposed over the substrate, a first lower electrode disposed over the one or more acoustic reflector layers, a first piezoelectric layer disposed over the first lower electrode, and a first upper electrode disposed over the first piezoelectric layer. The coupled resonator filter device further includes one or more acoustic coupling layers disposed over the first upper electrode, a second lower electrode disposed over the one or more acoustic coupling layers, a second piezoelectric layer disposed over the second lower electrode, a second upper electrode disposed over the second piezoelectric layer, and a first tuning capacitor having a first upper plate coupled to the first upper electrode and a first lower plate coupled to the first lower electrode.

An acoustic wave device includes a piezoelectric layer including lithium tantalate or lithium niobate, a dielectric film on the piezoelectric layer, the dielectric film including a dielectric material having a higher dielectric constant than that of the lithium tantalate or lithium niobate, and an IDT electrode on the dielectric film.