A high-frequency front end circuit includes an antenna terminal, a reception circuit that is directly or indirectly connected to the antenna terminal, and a transmission circuit that is directly or indirectly connected to the antenna terminal, wherein the transmission circuit has an amplification circuit, the amplification circuit includes an input terminal and an output terminal, an amplification element provided on a path connecting the input terminal and the output terminal, and a bias circuit having an LC resonance circuit and connected to between the amplification element and the output terminal. A frequency pass band of the transmission circuit is lower than a frequency pass band of the reception circuit, and a value of a resonant frequency of the bias circuit is smaller than a value of a frequency pass band width of the transmission circuit.

A power amplifier includes a two-dimensional matrix of NM active cells formed by stacking main terminals of multiple active cells in series. The stacks are coupled in parallel to form the two-dimensional matrix. The power amplifier includes a driver structure to coordinate the driving of the active cells so that the effective output power of the two-dimensional matrix is approximately NM the output power of each of the active cells.

The present disclosure describes a method and system for linearizing an amplifier using transistor-level dynamic feedback. The method and system enables nonlinear amplifiers to exhibit linear performance using one or more of gain control elements and phase shifters in the feedback path. The disclosed method and system may also allow an amplifier to act as a pre-distorter or a frequency/gain programmable amplifier.

A radio-frequency device comprises a first radio-frequency signal node, a second radio-frequency signal node, a first power cell path coupled between the first radio-frequency signal node and a ground reference node, the first power cell path including a first transistor having an input terminal coupled to the second radio-frequency signal node, and a second power cell path coupled in parallel with the first power cell path between the first radio-frequency signal node and the ground reference node, the second power cell path including a second transistor having an input terminal coupled to the second radio-frequency signal node and an output terminal that is electrically isolated from an output terminal of the first transistor.

A power amplification module includes a first amplification transistor that receives a first signal outputs an amplified second signal from the collector thereof; and a bias circuit that supplies a bias current to the base of the first amplification transistor. The first bias circuit includes a first transistor that is diode connected and is supplied with a bias control current; a second transistor that is diode connected, the collector thereof being connected to the emitter of the first transistor; a third transistor, the base thereof being connected to the base of the first transistor, and the bias current being output from the emitter thereof; a fourth transistor, the collector thereof being connected to the emitter of the third transistor and the base thereof being connected to the base of the second transistor; and a first capacitor between the base and the emitter of the third transistor.

An envelope tracking frontend device and a switch thereof are provided. The envelope tracking frontend device includes a power amplifier coupled, a switch and an envelope tracking module including an envelope tracking bias supply coupled between the signal generator and the switch. The switch includes a transmit-receive port, a transmit port coupled to the power amplifier, a receive port, a first terminal and a second terminal in series connection, and a third transistor and a fourth transistor as shunt transistors. The envelope tracking bias supply is configured to provide an envelope forward bias signal to the gate of the second transistor and the gate of the fourth transistor, and provide an envelope reverse bias signal to the gate of the first transistor and the gate of the third transistor such that an amplified signal is modulated before being provided by the switch.

A radio-frequency signal amplifier circuit that is used in a front-end circuit and that propagates a radio-frequency transmission signal and a radio-frequency reception signal is described. The amplifier circuit has an amplifier transistor, a bias circuit, a resistor, and an LC series resonance circuit. The LC series resonant circuit has one end that is connected to a node between the resistor and a signal input terminal, and has another end that is connected to a grounding terminal. A resonant frequency of the LC series resonance circuit is included in a difference frequency band between the frequencies of the transmission signal and the reception signal.

Apparatus and methods for power amplifier output matching is disclosed. In one aspect, there is provided an output matching circuit including an input configured to receive an amplified radio frequency signal from a power amplifier, a first output, and a second output. The output matching circuit further includes a first matching circuit electrically connected between the input of the output matching circuit and the first output, the first matching circuit configured to suppress harmonics of a fundamental frequency of the amplified radio frequency signal when the amplified radio frequency signal is within a first band. The output matching circuit further includes a second matching circuit electrically connected between the input of the output matching circuit and the second output, the second matching circuit configured to suppress harmonics of the fundamental frequency of the amplified radio frequency signal when the amplified radio frequency signal is within a second band different from the first band.

A low noise amplifier includes: an amplification unit including a first transistor and a second transistor connected in a cascode structure and configured to amplify a signal input to a control terminal of the first transistor; and a gain controller connected between a contact point at which the first transistor and the second transistor are connected to each other and a power source voltage, and configured to adjust a gain of the amplification unit.

A high-frequency module (1) includes a mounting substrate (90), a duplexer (60L) arranged on the mounting substrate (90), a duplexer (60H) arranged on the mounting substrate (90) and having a pass band with a higher frequency than a pass band of the duplexer (60L), and a semiconductor control IC (40) arranged on the mounting substrate (90) and stacked with the duplexer (60L) of the duplexers (60L and 60H).