Abstract: Acoustic resonator devices and filters are disclosed. An acoustic resonator includes a substrate and a single-crystal piezoelectric plate. A back surface of a supported portion of the piezoelectric plate is attached to a surface of the substrate. A portion of the piezoelectric plate forms a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on a front surface of the piezoelectric plate. The IDT includes first and second busbars, and interleaved fingers extending alternately from the first and second busbars. Overlapping portions of the interleaved fingers are disposed on the diaphragm. At least portions of both the first and second busbars are disposed on the supported portion of the piezoelectric plate.

Abstract: An acoustic resonator is fabricated by forming a patterned first photoresist mask on a piezoelectric plate at locations of a desired interdigital transducer (IDT) pattern. An etch-stop layer is then deposited on the plate and first photoresist mask. The first photoresist mask is removed to remove parts of the etch-stop and expose the plate. An IDT conductor material is deposited on the etch stop and the exposed plate. A patterned second photoresist mask is then formed on the conductor material at locations of the IDT pattern. The conductor material is then etched over and to the etch-stop to form the IDT pattern which has interleaved fingers on a diaphragm to span a substrate cavity. A portion of the plate and the etch-stop form the diaphragm. The etch-stop and photoresist mask are impervious to this etch. The second photoresist mask is removed to leave the IDT pattern.

Abstract: A radio-frequency circuit is used in simultaneous transfer of a radio-frequency signal of 4G and a radio-frequency signal of 5G, and includes a first transfer circuit that selectively receives the 4G radio-frequency signal or the 5G radio-frequency signal, and transfers a radio-frequency signal of a first communication band including a first transmission band and a first reception band and a radio-frequency signal of a second communication band including a second transmission band and a second reception band. The first and second transmission bands at least partially overlap. The first transfer circuit includes a first power amplifier that amplifies transmission signals of the first and second communication bands, and a first transmission filter that has a first passband including the first and second transmission bands, and passes the transmission signals of the first and second communication bands output from the first power amplifier.

Abstract: There are disclosed acoustic resonators and radio frequency filter devices. A back surface of a single-crystal piezoelectric plate is attached to a surface of a substrate except for portions of the piezoelectric plate forming a plurality of diaphragms, each of which spans a respective cavity in the substrate. A conductor pattern is formed on the front surface, the conductor pattern including interdigital transducers (IDTs) of one or more pairs of sub-resonators, each pair consisting of two sub-resonators. The IDT of each sub-resonator includes interleaved fingers disposed on a respective diaphragm. The piezoelectric plate and the IDTs are configured such that respective radio frequency signals applied to each IDT excite respective shear primary acoustic modes in the respective diaphragms. The two sub-resonators of each pair of sub-resonators are positioned symmetrically about a central axis.

Abstract: Zinc is added to a metal magnetic alloy powder including iron and silicon. An element is formed using this magnetic material, and a coil is formed inside or on the surface of the element.

Abstract: A metal magnetic particle provided with an oxide layer on a surface of an alloy particle containing Fe and Si. The oxide layer has a first oxide layer, a second oxide layer, a third oxide layer, and a fourth oxide layer. Also, in line analysis of element content by using a scanning transmission electron microscope-energy dispersive X-ray spectroscopy, the first oxide layer is a layer where Fe content takes a local maximum value, the second oxide layer is a layer where Fe content takes a local maximum value, the third oxide layer is a layer where Si content takes a local maximum value, and the fourth oxide layer is a layer where Fe content takes a local maximum value.

Abstract: A coil component includes a first outer magnetic body, a first outer insulator, a first inner magnetic body, an inner insulator, a second inner magnetic body, a second outer insulator, and a second outer magnetic body stacked sequentially, and a coil in the inner insulator and an internal magnetic body inside the coil. Volumes A, B, C, and D of the first and second outer insulators, the inner insulator, the coil, and the internal magnetic body, respectively, and volume E of the first outer magnetic body, the first inner magnetic body, the second inner magnetic body, and the second outer magnetic body satisfy 0.05?A?0.07, 0.2?B?0.4, 0.01?C?0.08, 0.03?D?0.05, and 0.4?E?0.71, where 0.05B?C?0.2B and A+B+C+D+E=1.

Abstract: A radio frequency circuit that supports simultaneous communication using downlink MIMO in a first band and uplink communication in a second band includes first and second power amplifiers connected to first and second antenna terminals, respectively. When a first SRS in the first band is output through the first antenna terminal, the first power amplifier amplifies the first SRS, according to a first deterioration amount of a signal-to-noise ratio in the first band due to distortion of a transmission signal in the second band having leaked in through the first antenna terminal, and when a second SRS in the first band is output through the second antenna terminal, the second power amplifier amplifies the second SRS, according to a second deterioration amount of the signal-to-noise ratio in the first band due to distortion of the transmission signal in the second band having leaked in through the second antenna terminal.

Abstract: A power amplifier circuit includes external input and output terminals; a first power amplifier with first input and output terminals, the first input terminal being connected to the external input terminal, the first output terminal being connected to the external output terminal; a second power amplifier having second input and output terminals, the second input terminal being connected to the external input terminal, the second output terminal being connected to the external output terminal; a power supply terminal that receives a power supply voltage that is supplied to the first power amplifier and controllably supplied to the second power amplifier; and a switch having first and second terminals, the first terminal being connected to the power supply terminal, the second terminal being connected to the second power amplifier.

Abstract: A highly reliable multilayer coil component in which the internal stress is further alleviated, and a method for producing the same. The method produces a multilayer coil component that includes an insulator portion, a coil that is embedded in the insulator portion and includes a plurality of coil conductor layers electrically connected to one another, and an outer electrode that is disposed on a surface of the insulator portion and is electrically connected to an extended portion of the coil. The method includes forming a conductive paste layer by using a conductive paste; forming an insulating paste layer by using an insulating paste; forming a multilayer compact that includes the conductive paste layer and the insulating paste layer; and firing the multilayer compact, in which the conductive paste has a PVC of 60% or more and 80% or less (i.e., from 60% to 80%).

Abstract: A thermal analysis method and apparatus, and a computer program that enable highly accurate heat transfer simulation of a structure or space, while reducing calculation costs. By performing thermal analysis on a structure or space using the calculation meshes generated by initial dividing means, the spatial distribution of heat flux vectors J and temperature gradient vectors ?T are calculated; by calculating the volume integrals of the inner products J·?T of the heat flux vectors J and the temperature gradient vectors ?T for individual partitioned regions and acquiring the absolute values of the volume integrals, thermal management sensitivity indices are calculated for the partitioned regions. Subsequently, partition of calculation meshes and subdivision of partitioned regions are performed on a predetermined number of partitioned regions that indicate greater indices among the calculated thermal management sensitivity indices, for example one partitioned region.

Abstract: An inductor component includes first and second internal wiring lines, an interlayer insulating layer between the first and second internal wiring lines and having a first main surface facing the first internal wiring line, a second main surface facing the second internal wiring line, and a via extending between the first main surface and the second main surface, and a via wiring line inserted through the via that electrically connects the first and second internal wiring lines. In a first section including a central axis of the via wiring line, the first main surface includes a first portion in contact with the first internal wiring line. The second main surface includes a second portion that is parallel to the first portion. A straight line that includes the first portion is a first reference line. A straight line that includes the second portion is a second reference line.

Abstract: An inductor component includes: a first internal conductor; a second internal conductor; an insulating interlayer disposed between the first internal conductor and the second internal conductor and having a first main surface on the first internal conductor side, a second main surface on the second internal conductor side, and a via extending therethrough between the first main surface and the second main surface; and a via conductor inserted through the via and electrically connecting the first internal conductor and the second internal conductor. In a first section including a central axis of the via conductor, the via conductor has a wedge portion interposed between the insulating interlayer and the first internal conductor in a direction parallel to the central axis.

Abstract: An inductor component includes a base body, first and second inner wiring line inside the base body, an inter-layer insulation layer, and a via-wiring line. The inter-layer insulation layer is inside the base body, and between the first and second inner wiring lines. The inter-layer insulation layer includes first and second major faces and a via-hole. The first major face faces the first inner wiring line. The second major face faces the second inner wiring line. The via-hole extends through the inter-layer insulation layer between the first and second major faces. The via-wiring line is in the via-hole, and electrically connects the first and second inner wiring lines. As seen in a first cross-section including a center axis of the via-wiring line, the via-wiring line includes a first portion in contact with the first inner wiring line, and a second portion in contact with the second inner wiring line.

Abstract: A power amplifier circuit includes an amplifier transistor having a collector terminal, an emitter terminal, and a base terminal, bias circuits, and a current limiter circuit. The bias circuit includes a constant current amplifier transistor that supplies direct-current bias current from an emitter terminal to the base terminal. The current limiter circuit includes a current limiting transistor an emitter terminal of which is connected to the bias circuit, a resistive element connected between the current limiting transistor and a power supply terminal, and a resistive element connected between the current limiting transistor and the constant current amplifier transistor. The bias circuit includes a constant current amplifier transistor that supplies direct-current bias current i3 from an emitter terminal to the base terminal.

Abstract: An electronic component includes a substrate and side wires. The substrate includes a first major surface, a second major surface, and a side surface. The side wires are on the side surface of the substrate and spaced apart from each other in a direction along an outer periphery of the substrate when viewed in plan in a thickness direction of the substrate. At least a portion of each of the side wires is provided indirectly on the side surface of the substrate. The electronic component further includes an electrically insulating layer interposed between the side surface of the substrate and the at least a portion of each of the side wires. Each of the side wires includes a bent portion bent when viewed in plan in the thickness direction of the substrate.

Abstract: An amplifier device includes an amplifier including cascade-connected power amplifiers in a plurality of stages and a bias circuit configured to supply bias currents to the amplifier. A bias current supplied to a power amplifier in the first stage of the power amplifiers in the plurality of stages exhibits a positive temperature characteristic. A bias current supplied to a power amplifier in the final stage exhibits a negative temperature characteristic.

Abstract: A multilayer resin substrate includes a base material including stacked resin layers including an opening resin layer, a conductor pattern, and an interlayer connection conductor. A concave portion is provided in the base material. The opening resin layer is closer to a first main surface than other resin layers. The concave portion includes a first opening portion provided by a cutting process from one surface of the opening resin layer, and another resin layer. The interlayer connection conductor is provided by filling a conductor in a second opening portion provided by a cutting process from an opposite surface of the opening resin layer. The end portion of the one surface of the first opening portion is not in contact with the conductor pattern.

Abstract: A hydrocarbon reforming catalyst for producing a synthesis gas containing hydrogen and carbon monoxide from a hydrocarbon-based gas, the hydrocarbon reforming catalyst containing a complex oxide having a perovskite structure including at least Ba, Zr, and Ru; and a hydrocarbon reforming apparatus that includes the hydrocarbon-reforming catalyst.

Abstract: Disclosed herein is a stress sensor that includes a stress detection layer including a laminated body including a first ferromagnetic layer, a first non-magnetic layer, a second ferromagnetic layer, and an antiferromagnetic layer stacked one on another. The antiferromagnetic layer includes Mn, and the magnetization direction of the second ferromagnetic layer is fixed by the exchange bias caused by the exchange coupling with the antiferromagnetic layer. The stress sensor detects a stress by an electric resistance depending upon a relative angle between magnetization directions of the first ferromagnetic layer and the second ferromagnetic layer, the relative angle changing depending upon an externally applied stress.