A radio frequency (RF) power amplifier includes an amplifying stage that includes an amplifying module, an input module and a feedback module. The amplifying module receives an RF to-be-amplified signal, and performs power amplification on the RF to-be-amplified signal to generate an RF output signal. The input module receives an RF input signal. The feedback module receives the RF output signal, cooperates with the input module to provide the RF to-be-amplified signal based on the RF input and output signals, and cooperates with the amplifying module to forma positive feedback loop that provides a loop gain which is less than one.

Radio frequency devices and methods are provided where a network like a filter network or impedance matching network comprises a series connection of at least two inductors.

An amplifier according to an embodiment of the present disclosure includes a first transistor and a first matching circuit. The first matching circuit is connected between an input terminal and a control terminal of the first transistor. The first matching circuit includes a first inductor, a second inductor, and a first switch. The first inductor has an end connected to the control terminal. The second inductor has an end connected to the other end of the first inductor. The first switch is configured to selectively switch between electrical continuity between the input terminal and the other end of the first inductor and electrical continuity between the input terminal and the other end of the second inductor.

A power amplifier includes a common source amplifier and a common gate amplifier circuit. The common source amplifier circuit has a terminal connected to a radio frequency (RF) input terminal and uses a source terminal commonly as an input terminal and an output terminal of the power amplifier. The common gate amplifier circuit has a terminal connected to the common source amplifier circuit and another terminal connected to an RF output terminal, and uses a gate terminal commonly as the input terminal and the output terminal of the power amplifier. The common gate amplifier circuit includes a Doherty amplifier including a main power amplifier and an auxiliary power amplifier that is connected to the main power amplifier in parallel.

A scalable periphery tunable matching power amplifier is presented. Varying power levels can be accommodated by selectively activating or deactivating unit cells of which the scalable periphery tunable matching power amplifier is comprised. Tunable matching allows individual unit cells to see a constant output impedance, reducing need for transforming a low impedance up to a system impedance and attendant power loss. The scalable periphery tunable matching power amplifier can also be tuned for different operating conditions such as different frequencies of operation or different modes.

A power amplifier module can be formed that includes metamaterial matching circuits. This power amplifier module can be included as part of a front-end module of a wireless device. The front-end module can replace a passive duplexer with an active duplexer that uses the power amplifier module in combination with a low noise amplifier circuit that can include a metamaterial matching circuit. The combination of PA and LNA circuits that utilize metamaterials can provide the functionality of a duplexer without including a stand-alone or passive duplexer. Thus, in certain cases, the front-end module can provide duplexer functionality without including a separate duplexer. Advantageously, in certain cases, the size of the front-end module can be reduced by eliminating the passive duplexer. Further, the loss introduced into the signal path by the passive duplexer is eliminated improving the performance of the communication system that includes the active duplexer.

A wireless communication device includes a signal generator supply a signal to an input node to which a power amplifier is connected. The power amplifier includes an inverter including a first transistor with a gate connected to the input node via a first signal path and a second transistor with a gate electrode connected to the input node via a second signal path. An output signal corresponding to the signal supplied to the input node is supplied from an output node between the first and second transistors. A filter is connected to the output node and outputs a filtered signal having a high frequency component removed. A bias application unit applies a first bias voltage to the first signal path and a second bias voltage to the second signal path. Levels of the bias voltages being set according to a direct current component in the filtered signal.

Size reduction is enabled. A power amplifying circuit includes a splitter, a first amplifier, a second amplifier, and a third amplifier. The splitter splits an input signal into a first signal and a second signal. The first amplifier has a first input terminal and a first output terminal, amplifies the first signal, and outputs a first amplified signal. The second amplifier has a second input terminal and a second output terminal, amplifies the second signal, and outputs a second amplified signal. The third amplifier has a third input terminal and a third output terminal, amplifies the first signal, and outputs a third amplified signal. The first output terminal and the second output terminal are connected to each other, the third input terminal is connected to the first input terminal, and the third output terminal is connected to the second output terminal.

The disclosure relates to a 5th generation (5G) or a pre-5G communication system for supporting a higher data transmission rate after a 4th generation (4G) communication system such as long-term evolution (LTE). A Doherty power amplifier of a wireless communication system is provided. The Doherty power amplifier includes a first power amplifier, a second power amplifier, a first transmission line connected to an output end of the first power amplifier, a second transmission line connected to an input end of the second power amplifier, a first network, and a second network, the first network may interconnect a first node connected with one end of the first transmission line and a second node connected with an output end of the second power amplifier, the one end of the first transmission line may be positioned on an opposite side with respect to the output end of the first power amplifier, and the second network may connect the first node, the second node, and a third node which is an output end of the Doherty power amplifier.

A power amplifier circuit includes first and second transistors and a first voltage output circuit. A radio frequency signal is input into a base of the first transistor. The first voltage output circuit outputs a first voltage in accordance with a power supply voltage. The first voltage is supplied to a base or a gate of the second transistor. An emitter or a source of the second transistor is connected to a collector of the first transistor. A first amplified signal generated by amplifying the radio frequency signal is output from a collector or a drain of the second transistor.