Abstract: In a high frequency device, resonators (IDT capacitors) that function as capacitors are included in a lumped constant balun included in a filter or duplexer, and furthermore, the resonance frequency of the IDT capacitors is set higher than the passband frequency of the filter. This improves the capacitor Q value, thus enabling the realization of a low-loss balance filter.

Abstract: According to an aspect of the invention, each of a filter, a duplexer and a communication module includes a plurality of series resonators connected to a signal line in series and a plurality of parallel resonators connected to the signal line in parallel. At least two of the plurality of parallel resonators are connected to the signal line between two of the plurality of series resonators in parallel, inductors are respectively connected to the at least two parallel resonators, and the inductors have different inductances from each other.

Abstract: A demultiplexer has a common terminal, a transmission terminal, and a reception terminal, and furthermore includes a transmission filter connected between the common terminal and the transmission terminal, a reception filter connected between the common terminal and the reception terminal, and a phase shift circuit connected in series to the reception filter connected between the common terminal and the reception terminal. A node on the line from the phase shift circuit to the common terminal or the transmission terminal, and a node on the line from the phase shift circuit to the reception terminal are coupled via a reactance. Accordingly, it is possible to fundamentally reduce or eliminate the situation in which transmission signals from the transmission filter arrive at the reception circuit, and improve isolation.

Abstract: A duplexer includes a common terminal, receiving filters, a transmitting filter, and a hybrid having four terminals (terminals 1 to 4). A first terminal (terminal 1), which is one of the four terminals of the hybrid is connected to the common terminal, the receiving filters are connected to a second terminal and a third terminal to which a signal is transmitted if it is input from the first terminal, and a transmitting filter is connected to a fourth terminal (terminal 4) of the hybrid. Thus, it is possible to improve the isolation of the duplexer, while avoiding an increase in the number of parts as well as greater complexity.

Abstract: A duplexer includes two surface acoustic wave (SAW) filters having different center frequencies; a phase matching circuit that matches phases of the two SAW filters; a package in which the SAW filters and the phase matching circuit are housed, the package being composed of multiple layers; and a line pattern provided between at least one of the SAW filters and at least one of a transmit terminal and a receive terminal of the duplexer. The line pattern runs on at least two of the multiple layers within a range defined by peripheral ground patterns provided in the package.

Abstract: A filter includes: a converter circuit, provided with a single-type common terminal and two balanced terminals, for performing conversion between a balanced line and an unbalanced line; two filter units coupled to each of the balanced terminals of the converter circuit and allowing passage of a signal in a pass band; and a bridging capacitor arranged to extend across the converter circuit and one of the filter units in a bridging manner, wherein the inductance of an opposite-side line of one of the filter units relative to the converter circuit is electromagnetically coupled to the inductance of a line coupling the other filter unit and the converter circuit.

Abstract: A duplexer includes a substrate including an insulation layer, an upper interconnection layer provided on an upper surface of the insulation layer, a lower interconnection layer provided on a lower surface of the insulation layer, and an inner interconnection layer provided in the insulation layer, the inner interconnection layer including an inner ground pad, at least one acoustic wave filter chip mounted on an upper surface of the substrate, signal pads provided on the upper interconnection layer and connected to signal electrodes of the at least one acoustic wave filter chip, and an upper ground pad that is provided in the upper interconnection layer so as to be located between the signal pads and is connected to a ground electrode of the at least one acoustic wave filter, wherein D1>D2 and D1>T1 where D1 is a minimum distance between the signal pads and the upper ground pad, D2 is a minimum distance between the signal pads and the inner ground pad, and T1 is a thickness of the insulation layer betwe

Abstract: A piezoelectric thin-film resonator includes: a lower electrode that is formed on a substrate; a piezoelectric film that is formed on the lower electrode; and an upper electrode that is formed on the piezoelectric film. In the piezoelectric thin-film resonator, the upper electrode has a greater film thickness than the lower electrode.

Abstract: A substrate for mounting a filter has a connection line layer having a transmission line for connecting a filter, a ground layer placed below the connection line layer and having a ground, and an insulation layer placed between the transmission line and the ground layer and having a thickness which satisfies a characteristic impedance of the transmission line in a range 0.1 to 50 ohms, the characteristic impedance determined by the thickness and a dielectric constant of the insulation layer and a width of the transmission line.

Abstract: A piezoelectric thin-film resonator includes a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film so as to have a portion that overlaps the lower electrode across the piezoelectric film. At least a part of an outer end of the piezoelectric film is further in than an outer end of an opposing region in which the upper and lower electrodes overlap each other across the piezoelectric film.

Abstract: A filter includes multiple piezoelectric thin-film resonators each having a substrate, a lower electrode formed on the substrate, a piezoelectric film formed on the lower electrode, and an upper electrode provided on the piezoelectric film so that the upper electrode and the lower electrode face each other across the piezoelectric film. The multiple piezoelectric thin-film resonators include a first resonator in which at least a part of an outer curved portion of the piezoelectric film of the first resonator is located further out than an outer curved portion of a region in which the upper electrode and the lower electrode face each other across the piezoelectric film.

Abstract: A duplexer includes: first and second filters including film bulk acoustic resonators (FBARs) arranged in a ladder form; first and second integrated-passive devices (IPDs) provided between a common terminal and the first and second filters; and a substrate on which the first and second filters and the first and second IPDs are mounted. The substrate includes conductive patterns that realize inductances connected between the first and second filters and ground. The first and second IPDs includes inductors connected to the first and second filters.

Abstract: A piezoelectric thin-film resonator includes a lower electrode formed on a substrate to define a rounded dome-shaped cavity between the lower electrode and the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film. A membrane region is an overlapping region of the lower electrode and the upper electrode interposing the piezoelectric film and a projected area of the cavity onto the substrate includes the membrane region.

Abstract: A surface acoustic wave device includes at least one interdigital transducer having electrodes of a double-layered structure in which an upper film and an underlying film are laminated. The upper film has a main component of Al and a first metal of Ti added to the main component. The underlying film has a main component of Ti.

Abstract: A piezoelectric thin-film resonator includes a lower electrode provided on a substrate, a piezoelectric thin film provided on the lower electrode, and an upper electrode provided on the piezoelectric thin film. A membrane region is defined by a region where the upper electrode and the lower electrode overlap each other to sandwich the piezoelectric thin film therebetween and has an elliptical shape, and the lower electrode is also provided at an outer side of the membrane region in a region in which neither an extraction electrode of the upper electrode nor an extraction electrode of the lower electrode is provided.

Abstract: A piezoelectric thin-film resonator includes a film laminate formed on a device substrate, the film laminate including a lower electrode, a piezoelectric film provided on the device substrate and the lower electrode, and an upper electrode provided on the piezoelectric film. At least one of the upper and lower electrodes has an electrode leading portion that extends from an membrane in which the upper electrode overlaps with the lower electrode through the piezoelectric film and has a width narrower than that of the membrane.

Abstract: A filter includes multiple piezoelectric thin-film resonators each having a substrate, a lower electrode formed on the substrate, a piezoelectric film formed on the lower electrode, and an upper electrode provided on the piezoelectric film so that the upper electrode and the lower electrode face each other across the piezoelectric film. The multiple piezoelectric thin-film resonators include a first resonator in which at least a part of an outer curved portion of the piezoelectric film of the first resonator is located further out than an outer curved portion of a region in which the upper electrode and the lower electrode face each other across the piezoelectric film.

Abstract: A piezoelectric thin-film resonator includes a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film so as to have a portion that overlaps the lower electrode across the piezoelectric film. At least a part of an outer end of the piezoelectric film is further in than an outer end of an opposing region in which the upper and lower electrodes overlap each other across the piezoelectric film.

Abstract: An antenna duplexer includes two surface acoustic wave filters having different center frequencies and a phase matching circuit that matches phases of the two surface acoustic wave filters. A matching line pattern is provided on at least two layers between the two surface acoustic wave filters and transmission and reception terminals, and within an area specified by a sheet-like ground in a multilayered package, the multilayered package comprising multiple layers including a bonding layer on which wire bonding pads are provided for connecting to the two surface acoustic wave filters, and the matching line pattern having no portion provided on bonding layer.

Abstract: A duplexer includes a transmit filter of a ladder type filter, connected between a common terminal and a transmitting terminal, and a receive filter of the ladder type filter, connected between the common terminal and a receiving terminal. One or more parallel resonators in the transmit filter are grounded through a transmitting inductance, and a portion of multiple parallel resonators are grounded through a first receiving inductance and a remaining portion of the multiple parallel resonators are grounded through a second receiving inductance.