A power amplifier circuit includes a power amplifier including a first transistor having a first terminal connected to a reference potential, a second terminal to which a first current and a radio-frequency signal are input, and a third terminal connected to a first power supply potential via a first inductor; a capacitor connected to the third terminal of the first transistor; a second transistor including a first terminal connected to the capacitor and the reference potential via a second inductor, a second terminal to which a second current is input and is connected to the reference potential, and a third terminal connected to the first power supply potential via a third inductor and outputs signal; and an adjustment circuit that outputs a third current corresponding to the first power supply potential or a second power supply potential to the second terminal of the second transistor.

A push-pull radio frequency power amplifier includes a coupling feedback circuit, a drive stage circuit and a power output stage circuit, in which the coupling feedback circuit is connected with the drive stage circuit and/or the power output stage circuit; the coupling feedback circuit is configured to generate an alternating voltage at an input end of a first transistor and/or an input end of a push-pull transistor; when the alternating voltage and a voltage at the input end are in a same direction, a positive feedback of an input signal at the input end is achieved; and the first transistor represents a transistor in the drive stage circuit and the push-pull transistor represents a second transistor and a third transistor that form a push-pull structure in the power output stage circuit.

An amplifier circuit includes a first amplifier that amplifies a high frequency signal, and a load circuit that changes a load impedance of the first amplifier without being controlled by an external circuit so that a saturation power at a first temperature is higher than a saturation power at a second temperature lower than the first temperature, and an efficiency at the first temperature is lower than an efficiency at the second temperature.

An amplifier includes a first input transistor, a second input transistor, a first cascode transistor, a second cascode transistor, a first current mirror circuit, and a second current mirror circuit. The first input transistor is coupled to a first input terminal. The second input transistor is coupled to a second input terminal and the first input transistor. The first cascode transistor is coupled to the first input transistor. The second cascode transistor is coupled to the second input transistor and the first cascode transistor. The first current mirror circuit is coupled to the first cascode transistor, the second cascode transistor, and the first input terminal. The second current mirror circuit is coupled to the first cascode transistor, the second cascode transistor, and the second input terminal.

Provided is a high-gain amplifier based on double-gain boosting including a first gain amplification unit including a first amplifier, a second amplifier, and a an interstage matching network connected between the first amplifier and the second amplifier and performing primary amplification; and a second gain amplification unit connected in parallel with the first gain amplification unit and performing secondary boosting.

A dual-band MMIC power amplifier and method of operation to amplify frequencies in different RF bands while only requiring input drive signals at frequencies f.sub.1 and f.sub.2 in a narrow RF input band. This allows for the use of a conventional narrowband RF IC to drive the MMIC and does not require additional circuitry (e.g., a LO) on the MMIC power amplifier. The matching network of the last amplification stage is modified to pass f.sub.1 (or a harmonic thereof), reflect f.sub.2, pass a P.sup.th harmonic of f.sub.2 where P is 2 or 3 and to reflect any unused 1.sup.st, 2.sup.nd or 3.sup.rd order harmonics of f.sub.1 or f.sub.2 back into the MMIC. In response to an input signal at f.sub.1, the MMIC power amplifier amplifies and outputs a signal at f.sub.1 (or a harmonic thereof). In response to an input signal at f.sub.2 at sufficient RF power, the last amplification stage operates in compression such that the MMIC power amplifier generates the harmonics, selects the P.sup.th harmonic and outputs an amplified RF signal at P*f.sub.2.

Multiple example valve amplifiers are provided. A first example valve amplifier is provided which comprises (i) a valve power amplifier switchable between a high-power mode and a low-power mode and (ii) a loudspeaker simulator circuit, the valve amplifier being configured such that the valve power amplifier drives the loudspeaker simulator circuit in the low-power mode. A second example valve amplifier is provided which comprises a switched-mode power supply, SMPS, system), the SMPS system comprising (i) an SMPS and (ii) circuitry configured to enable an output impedance of the SMPS to be switched between first and second output impedances, the first output impedance being lower than the second output impedance.

The present disclosure is to improve the power added efficiency of a power amplifier at high output power. The power amplifier includes: a first capacitor with a radio frequency signal input to one end thereof; a first transistor whose base is connected to the other end of the first capacitor to amplify the radio frequency signal; a bias circuit for supplying bias to the base of the first transistor; and a second capacitor with one end connected to the base of the first transistor and the other end connected to the emitter of the first transistor.

The wireless RF semiconductor system is described for use in wireless communication devices that operate in frequency range from approximately 6 GigaHertz (GHz) to 100 GHz. The system comprises of at least one RF antenna and at least one RF integrated circuit fabricated (or built) on the same semiconductor substrate inside a one single packaged module. The wireless RF semiconductor system is described in a variety of different configurations with its functionality divided up over several single chip circuits. The system simplifies assembly, reduces size and cost, and allows for a quick time to market, while maximizing the RF performance demanded by fixed and mobile 4G, 5G and other wireless standards. The system uses a novel idea of configuration and packaging of active and passive RF components into a single module. This in turn allows RF manufacturers to unlock the potential of very high frequencies operation that were previously thought too expensive and unattainable to average user. The wireless RF semiconductor system can be implemented in both mobile solutions (such as phones and tablets) and fixed applications (such as repeaters, base-stations, and distributed antenna systems).

Radio frequency (RF) generators are disclosed. A RF generator may include an analog signal generator configured to generate a pulsed analog signal responsive to a digital pulsed waveform defined by one or more commands. The RF generator may also include a modulator configured to generate a pulsed radio frequency (RF) signal by modulating an RF carrier using the pulsed analog signal as a modulating signal. Further, the RF generator may include an amplification stage configured to amplify the pulsed RF signal output by the modulator. RF generation systems and methods of generating a pulsed RF signal also disclosed.