A filter module includes an inductor, a filter including first wiring, and second wiring between the inductor and the first wiring and being a direct-current floating potential. The inductor and the first wiring are magnetically coupled, the inductor and the second wiring are magnetically coupled, and the first wiring and the second wiring are capacitively coupled.

A circuit comprising a receive block, a transmit block, and an antenna multiplexer. The antenna multiplexer includes an input port coupled to the transmit block, an output port coupled to the receive block, a common port for coupling to an antenna, and a receive filter coupled between the common port and the output port. The receive filter includes a first plurality of resonators coupled together in series between the common port and the output port including a compensation resonator coupled directly to the output port. A first angular range of a reflection coefficient of the antenna multiplexer over a transmission frequency band measured looking into the output port of the antenna multiplexer does not overlap with a second angular range of the conjugate of the reflection coefficient of the low noise amplifier over the transmission frequency band measured looking into an input of the low noise amplifier.

A method of manufacturing a packaged surface acoustic wave filter chip is disclosed. The method can include providing a structure having first interdigital transducer electrodes formed with a first piezoelectric layer, second interdigital transducer electrodes formed with a second piezoelectric layer, and a substrate between the first and second piezoelectric layers. The method can include forming a plurality of through electrodes extending at least partially through a thickness of the structure such that a first set of through electrodes of the plurality of through electrodes are electrically connected to the first interdigital transducer electrodes and a second set of through electrodes of the plurality of through electrodes are electrically isolated from the first interdigital transducer electrodes.

A multiplexer includes a first filter located between a common terminal and a first terminal to pass a signal in a first passband, and a second filter located between the common terminal and a second terminal to pass a signal in a second passband. A first series arm circuit included in the first filter includes a first series arm resonator and a second series arm resonator. The first series arm circuit is connected to the common terminal not through a circuit including an elastic wave resonator and a connecting point of the circuit. The first series arm circuit has a first antiresonance frequency and a second antiresonance frequency higher than the first antiresonance frequency. The second antiresonance frequency is higher than a higher edge of the first passband. The first antiresonance frequency is at or lower than a higher edge of the second passband.

A surface acoustic wave filter includes series and parallel arm resonance sections. The series arm resonance section is in a series arm. The parallel arm resonance section is in a parallel arm. The series arm resonance section includes one or more surface acoustic wave devices. Each surface acoustic wave device includes a first resonator group and a second resonator group. The first and second resonator groups are connected in parallel and include surface acoustic wave resonators. The first resonator group includes at least one surface acoustic wave resonator. The second resonator group includes a greater number of surface acoustic wave resonators than the at least one surface acoustic wave resonator in the first resonator group. The resonant frequency of the surface acoustic wave resonator in the first resonator group is higher than the resonant frequency of the surface acoustic wave resonators in the second resonator group.

An elastic wave device includes a piezoelectric body including a main surface, an IDT electrode provided on the main surface of the piezoelectric body, and a wiring electrode provided on the main surface of the piezoelectric body and electrically connected to the IDT electrode, in which the wiring electrode includes a portion that extends to an edge of the main surface of the piezoelectric body, and a width of the wiring electrode on the edge is narrower than a width of the wiring electrode in a portion not on the edge.

A packaged acoustic wave component includes a support substrate, a multi-layer piezoelectric substrate disposed over a first side of the support substrate, one or more metal layers disposed on a second side of the support substrate that is opposite the first side of the support substrate, and one or more surface acoustic wave resonators or filters disposed over the multi-layer piezoelectric substrate. The one or more surface acoustic wave resonators or filters include a multi-mode surface acoustic wave resonator or filter (e.g., dual mode surface acoustic wave resonator or filter). One or more vias extend through the support substrate and electrically connect the multi-mode surface acoustic wave resonator or filter and the one or more metal layers to provide a ground connection for the multi-mode surface acoustic wave resonator or filter, while reducing parasitic inductance.

A surface acoustic wave (SAW) resonator is provided with reduced rattling at frequencies lower than the resonance value. The SAW resonator includes an interdigital transducer (IDT) on a piezoelectric substrate. The IDT includes a first set of interdigital electrodes distributed between and parallel to the first end of the IDT and the second end of the IDT and a second set of interdigital electrodes interleaved with the first plurality of interdigital electrodes. A first resonant cavity is formed a predetermined distance from the first end of the IDT, and a second resonant cavity is formed a predetermined distance from the second end of the IDT. Additionally, a radio frequency (RF) filter is provided that includes multiple SAW resonators that include the resonant cavities formed a predetermined distance from the first and second ends of the IDT. This RF filter may provide increased bandwidth and reduced insertion loss.

A filter includes: a piezoelectric substrate; one or more series resonators that are located on the piezoelectric substrate and are connected in series between an input terminal and an output terminal; at least one series resonator that is connected between a first node and a second node, is included in the one or more series resonators, and includes a reflector that is grounded, the first node and the second node being located between the input terminal and the output terminal; and a cancel line that is connected in parallel with the at least one series resonator between the first node and the second node, and cancels a signal outside a passband propagating through the at least one series resonator from the first node to the second node.

A duplexer includes a transmission filter with a ladder circuit configuration and a reception filter including a ladder filter portion connected to an antenna terminal and a longitudinally coupled resonator-type surface acoustic wave filter. In the transmission filter, a coupling capacitor is connected between an end portion of an inductor nearer to parallel arm resonators and a wiring line connecting the series arm resonators of the ladder filter portion to each other in the reception filter.