A wafer-level chip-scale package includes a polymeric body having a conductive via passing through the polymeric body and a piezoelectric substrate directly bonded to an upper end of the conductive via. The wafer-level chip-scale package further includes a cavity defined between a portion of the polymeric body and the piezoelectric substrate and a metal seal ring disposed in the body and having an upper end bonded to the piezoelectric substrate, the metal seal ring passing only partially through the body.

A SAW filter includes a piezoelectric substrate, a serial arm and a parallel resonance portion. The serial arm includes one or more serial resonance portions. The parallel resonance portion is located on the piezoelectric substrate and configures a ladder-type filter together with the serial arm. The parallel resonance portion includes a parallel resonator and a capacity element. The parallel resonator includes an IDT electrodes on the piezoelectric substrate and a pair of reflectors on the two sides thereof. The capacity element is connected in parallel with the parallel resonator. A capacitance of the capacity element is 0.8 time or more of a capacitance of the IDT electrode in the parallel resonator. A difference between an anti-resonance frequency and a resonance frequency of the first parallel resonance portion is smaller than a difference between an anti-resonance frequency and a resonance frequency of the first parallel resonator.

A communication module includes: a first substrate having a first surface; a second substrate having a second surface, the second surface facing the first surface across an air gap; a first filter located on the first surface, a passband of the first filter being either one of a transmit band and a receive band of a first band, the first band being a frequency division duplex band; and a second filter located on the second surface, at least a part of the second filter overlapping with at least a part of the first filter in a stacking direction in which the first substrate and the second substrate are stacked, a passband of the second filter being at least one of a transmit band and a receive band of a second band, the second band differing from the first band.

A multiplexer includes a common terminal, a first filter configured to be connected to the common terminal, and having a first passband, a second filter configured to be connected to the common terminal, and having a second passband that at least partially overlaps the first passband, and a third filter configured to be connected to the common terminal, and having a third passband that does not overlap both the first passband and the second passband.

An elastic wave device includes a substrate, an elastic wave element, and an exterior resin layer. The substrate includes an outer electrode on one main surface thereof and a first mounting electrode on another main surface thereof. The elastic wave element includes a piezoelectric substrate, a transmission functional electrode, a reception functional electrode, and ground terminals on one main surface of the piezoelectric substrate, and the ground terminals are connected to the first mounting electrode. High-thermal-conductivity conductor layers are provided on another main surface of the piezoelectric substrate, conductor vias penetrate between both main surfaces of the piezoelectric substrate, and the high-thermal-conductivity conductor layers and the ground terminals are connected to each other by the conductor vias.

A composite filter device includes a common terminal disposed on an element substrate including a piezoelectric layer, first and second band pass filters disposed on the element substrate, and connected at one end thereof to the common terminal, a shield electrode interposed between a signal line and the first band pass filter, the signal line being disposed on the element substrate and connecting the common terminal to the first and second band pass filters, and an inductor connected between the shield electrode and a reference potential line.

An elastic wave device includes a first piezoelectric substrate made of LiNbO.sub.3, a first band-pass filter provided on the first piezoelectric substrate and including first IDT electrodes, a dielectric layer provided on the first piezoelectric substrate and covering the plurality of first IDT electrodes, a second piezoelectric substrate, a second band-pass filter provided on the second piezoelectric substrate, including second IDT electrodes, and differing from the first band-pass filter in pass band, and a band elimination filter connected to the first band-pass filter. The band elimination filter is provided on a piezoelectric substrate other than the first piezoelectric substrate.

Embodiments of this disclosure relate to reducing coupling between acoustic wave resonators. An isolation region of a substrate can be located between acoustic wave resonators. The isolation region can reduce capacitive coupling through the substrate between the acoustic wave resonators. In certain embodiments, the isolation region can be located between acoustic wave resonators of different filters to thereby increase isolation between the filters.

Embodiments of this disclosure relate to methods of manufacturing acoustic wave components that include acoustic wave resonators that share a substrate. Laser light can be applied to alter a region of the substrate that is located between two of the acoustic wave resonators. Altering the region with laser light can reduce coupling between the two acoustic resonators through the substrate. The substrate can be monolithic after laser the light is applied.

Aspects and examples provide electronic elements and filter devices configured to prevent deterioration of the propagation characteristics caused by input and output signals being electromagnetically coupled to an electric conductor side wall. In one example an electronic filter includes an element substrate having a top surface, a bottom surface, a side surface, and piezoelectric body. A circuit including a plurality of SAW resonators is formed on the top surface of the element substrate. The electronic filter further includes a sealing substrate having a top surface and a bottom surface, and a side wall including an electric conductor and formed to define a cavity between the top surface of the element substrate and the bottom surface of the sealing substrate, the side wall enclosing a periphery of the circuit and being connected to a ground potential of the circuit.