An acoustic wave filter device includes first and second acoustic wave filters provided on a piezoelectric substrate, an insulating layer that is provided on the piezoelectric substrate and has a smaller dielectric constant than the piezoelectric substrate, a first wiring conductor electrically connected to an electrode of the first acoustic wave filter, a second wiring conductor electrically connected to an electrode of the second acoustic wave filter, the first wiring conductor and the second wiring conductor facing each other on the insulating layer in plan view, and a ground conductor located between the insulating layer and the piezoelectric substrate in a region A circumscribing the first wiring conductor and the second wiring conductor on the insulating layer in plan view.

A radio-frequency module includes a multilayer substrate, an input switch, an output switch, and filters. A switch IC is disposed on a main surface of the multilayer substrate. The input switch is disposed in the switch IC and includes a first input terminal and first output terminals. The output switch is disposed in the switch IC and includes second input terminals and a second output terminal. The filters are disposed outside the switch IC and are connected to the first output terminals and the second input terminals. In a plan view of the multilayer substrate, the first input terminal and the first output terminals are disposed close to a first side of an exterior of the switch IC, and the second input terminals and the second output terminal are disposed close to a second side different from the first side of the exterior of the switch IC.

A filter includes a series arm circuit connected between an input-output terminal and an input-output terminal and a parallel arm circuit connected between a ground and a node. The parallel arm circuit includes a first circuit and a second circuit. The first circuit has a parallel arm resonator. The second circuit is connected in parallel with the first circuit and has a parallel arm resonator. At least one of the first and second circuits includes a variable frequency circuit. The variable frequency circuit is connected in series with the parallel arm resonator or the parallel arm resonator included in the corresponding one of the first and second circuits. The variable frequency circuit has an impedance element and a switch connected in parallel with each other. The parallel arm resonator has a resonant frequency different from the parallel arm resonator and an anti-resonant frequency different from the parallel arm resonator.

Various examples are provided for highly reconfigurable multiband radio frequency (RF) filters. The multiband RF filters can be continuously tunable. In one example, a multiband RF filter includes a Lyot loop filter that can generate an optical comb using an input optical signal from a tunable Mach-Zehnder interferometer (MZI), a birefringent device, and a polarization rotation angle of a polarization controller. The tunable MZI can include a tunable delay line that can adjust comb spacing of the optical comb. In another example, a multiband RF filter includes a second MZI in series with a first MZI. The second MZI can generate a second tunable output signal from a first tunable output signal from the first MZI. In another example, the multiband RF filter can include a third MZI in series with the second MZI. The third MZI can generate a third tunable output signal from the second tunable output signal.

A radio-frequency module includes a multilayer substrate, an input switch, an output switch, and filters. A switch IC is disposed on a main surface of the multilayer substrate. The input switch is disposed in the switch IC and includes a first input terminal and first output terminals. The output switch is disposed in the switch IC and includes second input terminals and a second output terminal. The filters are disposed outside the switch IC and are connected to the first output terminals and the second input terminals. In a plan view of the multilayer substrate, the first input terminal and the first output terminals are disposed close to a first side of an exterior of the switch IC, and the second input terminals and the second output terminal are disposed close to a second side different from the first side of the exterior of the switch IC.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

An example resonating structure comprises a substrate, a resonator body, and an anchoring body for anchoring the resonator body to the substrate. The resonator body includes a layer of base material and, deposited on top of the layer of base material, a layer of mismatch material having a mismatch in temperature coefficient of elasticity (TCE) relative to the base material. The base material is doped with a dopant having a concentration chosen so as to minimize a second order temperature coefficient of frequency for the resonator body. The thickness of the layer of the mismatch material is chosen so as to minimize a first order temperature coefficient of frequency for the resonator body.

A dual-mode resonator, devices employing the dual-mode resonator, and the methods of making the resonator and the devices are disclosed. Embodiments include a dual-mode resonator including a semiconductor substrate; a material on the semiconductor substrate, having a cavity formed therein; a seed layer over the cavity in a V-shape, wherein sides of the V-shape form an angle of 15 to 25 degrees with a horizontal line; a bottom electrode on the seed layer; an acoustic layer on the bottom electrode; a top electrode on the acoustic layer; and a mass loading layer on the top electrode; and a cap over the dual-mode resonator.

Power conversion systems and filters therefor include conductive busbars, a first low frequency capacitor circuit coupled with the busbars at a first location proximate a filter input, a first inductor circuit with common mode cores extending around the busbars at a second location between the first location and a filter output, a second low frequency capacitor circuit coupled with the busbars at a third location between the second location and the filter output, a second inductor circuit with second common mode cores extending around the busbars at a fourth location between the third location and the filter output, a third low-frequency capacitor circuit coupled with the busbars at a fifth location between the fourth location and the filter output, and a high frequency fourth capacitor circuit, coupled with one of the busbars at the fifth location.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.