An amplifier circuit is configured in such a way that the amplifier circuit includes: a first amplifier to amplify a signal to be amplified; an output matching circuit through which the signal amplified by the first amplifier propagates; and a second amplifier to amplify the signal which has propagated through the output matching circuit, and the output matching circuit is a lumped constant circuit including multiple lumped constant elements, and, by using the multiple lumped constant elements, transforms the impedance seen on the second amplifier side from the first amplifier when the output power of the second amplifier is lower than saturation electric power, to impedance higher than impedance seen on the second amplifier side from the first amplifier when the output power of the second amplifier is equal to the saturation electric power.

A power amplification circuit can include an input impedance matching circuit associated with one or more frequency bands of a plurality of frequency bands. The power amplification circuit can include a transistor with respective input coupled to an output of the input impedance matching circuit. The power amplification circuit can include a plurality of output impedance matching circuits. Each output impedance matching circuit can be associated with a respective frequency band of the plurality of frequency bands. The power amplification circuit can include a single pole multi-throw (SPMT) switch having an input terminal connected to an output of the transistor and a plurality of output terminals. Each output terminal of the SPMT switch can be connected to a corresponding output impedance matching circuit of the plurality of output impedance matching circuits.

A multi-band power amplifier module includes at least one transmission input terminal, at least one power amplifier circuit that receives a first transmission signal and a second transmission signal through the at least one transmission input terminal, a first filter circuit that allows the first transmission signal to pass therethrough, a second filter circuit that allows the second transmission signal to pass therethrough, at least one transmission output terminal through which the first and second transmission signals output from the first and second filter circuits are output, a transmission output switch that outputs each of the first and second transmission signals output from the at least one power amplifier circuit to the first filter circuit or the second filter circuit, and a first tuning circuit that adjusts impedance matching between the at least one power amplifier circuit and the at least one transmission output terminal.

A multi-band power amplifier module includes at least one transmission input terminal, at least one power amplifier circuit that receives a first transmission signal and a second transmission signal through the at least one transmission input terminal, a first filter circuit that allows the first transmission signal to pass therethrough, a second filter circuit that allows the second transmission signal to pass therethrough, at least one transmission output terminal through which the first and second transmission signals output from the first and second filter circuits are output, a transmission output switch that outputs each of the first and second transmission signals output from the at least one power amplifier circuit to the first filter circuit or the second filter circuit, and a first tuning circuit that adjusts impedance matching between the at least one power amplifier circuit and the at least one transmission output terminal.

Describe is a buffer which comprises: a differential source follower coupled to a first input and a second input; first and second current steering devices coupled to the differential source follower; and a current source coupled to the first and second current steering devices. The buffer provides high supply noise rejection ratio (PSRR) together with high bandwidth.

Describe is a buffer which comprises: a differential source follower coupled to a first input and a second input; first and second current steering devices coupled to the differential source follower; and a current source coupled to the first and second current steering devices. The buffer provides high supply noise rejection ratio (PSRR) together with high bandwidth.

A system for adapting the voltage of a drain of a power stage includes at least two transmission paths T.sub.Xa, a transmission path comprising a resistive element (1.sub.n), a phase control module (2.sub.n), and a power stage (3.sub.n) at the output of which a radiating element (E.sub.n) is arranged, comprising at least: a device (5.sub.n) for determining the value of a reflected power P.sub.r, the value of an incident power P.sub.i in a power stage, and the ratio of the powers R, an analogue device (6.sub.n) configured so as to pulse width-modulate the difference signal, a switching cell (7.sub.n) receiving a low-power PWM signal and designed to generate a power signal PWM.sub.a that is transformed, by a low-pass filter (8.sub.n), into a bias signal for biasing the power stage in accordance with a predefined bias control law.

A fast-switching average power tracking (APT) power management integrated circuit (PMIC) is provided. The fast-switching APT PMIC includes a voltage amplifier(s) and an offset capacitor(s) having a small capacitance (e.g., between 10 nF and 200 nF). The voltage amplifier(s) is configured to generate an initial APT voltage(s) based on an APT target voltage(s) and the offset capacitor(s) is configured to raise the initial APT voltage(s) by an offset voltage(s) to generate an APT voltage(s). In embodiments disclosed herein, the offset voltage(s) is modulated based on the APT target voltage(s). Given the small capacitance of the offset capacitor(s), it is possible to adapt the offset voltage(s) fast enough to thereby change the APT voltage(s) within a predetermined temporal limit (e.g., 0.5 μs). As a result, the fast-switch APT PMIC can enable a power amplifier(s) to support dynamic power control with improved linearity and efficiency.

A distributed power amplifier includes radio frequency (RF) input and output terminals. A first field effect transistor (FET) is coupled at a first gate terminal to the RF input terminal and at a first drain terminal to the RF output terminal. The first FET has a first periphery and a first source terminal electrically connected to ground potential. A second FET has a second periphery smaller than the first periphery. The second FET has a second gate terminal electrically coupled to the first gate terminal through a first inductor, a second drain terminal electrically coupled to the first drain terminal through a second inductor, and a second source terminal electrically connected to the ground potential. A drain voltage terminal, which excludes a resistive element, is electrically coupled to a drain bias network through which a drain bias voltage is applied to the first drain terminal and the second drain terminal.

A method of a wireless transmitter is disclosed. The method is for mitigation of distortion caused by non-linear hardware components of the transmitter, wherein mitigation of distortion comprises mitigating at least one intermodulation component, wherein the transmitter is configured to process an input signal having an input signal spectrum, and wherein the transmitter comprises two or more signal branches, each signal branch comprising a respective non-linear hardware component. The method comprises modifying the input signal for a first one of the signal branches by applying a first phase shift to a first part of the input signal spectrum, wherein the first phase shift has a first sign and a first absolute value, and applying a second phase shift to a second part of the input signal spectrum. The second phase shift has a second sign which is opposite to the first sign, and a second absolute value which is equal to the first absolute value. The first and second parts are non-overlapping. The method also comprises modifying the input signal for a second one of the signal branches by applying the first phase shift to the second part of the input signal spectrum, and applying the second phase shift to the first part of the input signal spectrum. The method further comprises feeding the modified input signals to respective ones of the signal branches. Corresponding apparatus, wireless transmitter, communication device, and computer program product are also disclosed.