Abstract: A transmit/receive module includes plural duplexers, a power amplifier, and a sending transmission line. The plural duplexers operate in bands different from each other and each includes a transmit filter and a receive filter. The power amplifier amplifies signals of pass bands of the plural transmit filters and outputs the amplified signals. The sending transmission line is connected to the plural transmit filters. The signals of the pass bands of the plural transmit filters output from the power amplifier are transmitted through the sending transmission line.

Abstract: A filter device includes a piezoelectric substrate, a dielectric layer on the piezoelectric substrate, a first IDT electrode on the dielectric layer, a second IDT electrode positioned on the piezoelectric substrate in an area where the dielectric layer is not provided such that the first and second IDT electrodes are side by side in an acoustic wave propagation direction extending along a principal surface of the piezoelectric substrate, a first reflector on the dielectric layer and adjacent to the first IDT electrode on a side of the second IDT electrode, and a second reflector on the piezoelectric substrate and adjacent to the second IDT electrode on a side of the first IDT electrode. The dielectric layer includes an edge portion between the first and second reflectors in planar view seen from a stacking direction of the piezoelectric substrate and the dielectric layer.

Abstract: 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.

Abstract: Provided are a power amplifier circuit and a communication device that improve a power handling capability required for a filter while increasing output power. A power amplifier circuit includes: an amplifier unit that amplifies an input signal of a time division duplex scheme and outputs a signal to a signal path and a signal to a signal path; a filter that is provided in the signal path and outputs a signal based on the signal; a filter that is provided in the signal path and outputs a signal based on the signal; and a transformer that is connected to the signal path through the filter and connected to the signal path through the filter and outputs an output signal based on the signal and the signal to a signal path.

Abstract: A filter device includes a first series line, one or more first parallel lines extending from the first series line, two or more first series IDT electrodes on the first series line, and one or more first parallel IDT electrodes on the one or more first parallel lines. At least one of the two or more first series IDT electrodes is a first-type electrode. A dielectric layer is between the first-type electrode and a substrate. At least one of the two or more first series IDT electrodes except the first-type electrode and the one or more first parallel IDT electrodes is a second-type electrode directly contacting the substrate. A first series IDT electrode of the two or more first series IDT electrodes that has a largest pitch of electrode fingers is the first-type electrode.

Abstract: A filter device includes series and parallel arm resonators provided at a filter chip and inductors electrically connected in series with respective ones of the parallel arm resonators. A first inductor having the highest inductance of the inductors is electrically connected in series with a first parallel arm resonator having the highest anti-resonant frequency of the parallel arm resonators. One end of the first parallel arm resonator and one end of a second parallel arm resonator in other ones of the parallel arm resonators are electrically connected to a same wiring line in wiring lines separated by the series arm resonators on a line electrically connecting an input terminal and an output terminal of the filter chip. The other ends of the first and second parallel arm resonators are respectively electrically connected to first and second ground terminals of the filter chip.

Abstract: A filter device includes series and parallel arm resonators provided at a filter chip and inductors electrically connected in series with respective ones of the parallel arm resonators. A first inductor having the highest inductance of the inductors is electrically connected in series with a first parallel arm resonator having the highest anti-resonant frequency of the parallel arm resonators. One end of the first parallel arm resonator and one end of a second parallel arm resonator in other ones of the parallel arm resonators are electrically connected to a same wiring line in wiring lines separated by the series arm resonators on a line electrically connecting an input terminal and an output terminal of the filter chip. The other ends of the first and second parallel arm resonators are respectively electrically connected to first and second ground terminals of the filter chip.

Abstract: A transmit/receive module includes plural duplexers, a power amplifier, and a sending transmission line. The plural duplexers operate in bands different from each other and each includes a transmit filter and a receive filter. The power amplifier amplifies signals of pass bands of the plural transmit filters and outputs the amplified signals. The sending transmission line is connected to the plural transmit filters. The signals of the pass bands of the plural transmit filters output from the power amplifier are transmitted through the sending transmission line.