A high frequency amplifier includes an asymmetric Doherty amplifier configured to amplify a high frequency signal having a wavelength A, the high frequency signal being input, and the asymmetric Doherty amplifier including a carrier amplifier and a peak amplifier, the peak amplifier being configured to start an amplifying operation when an output of the carrier amplifier reaches a saturation region and having a saturation output different from a saturation output of the carrier amplifier, a driver amplifier configured to drive the asymmetric Doherty amplifier, a branch circuit configured to branch the high frequency signal amplified by the driver amplifier into an input path on a peak amplifier side and an input path on a carrier amplifier side, a phase adjustment circuit configured to delay either a phase of a signal input to the peak amplifier or a phase of a signal input to the carrier amplifier, the phase adjustment circuit being provided on either the input path on the peak amplifier side or the input path on the carrier amplifier, a first substrate on which the carrier amplifier and the peak amplifier are mounted, and a second substrate on which the driver amplifier, the branch circuit, and the phase adjustment circuit are mounted. An input terminal of the driver amplifier and an input terminal of the carrier amplifier are disposed at positions where the input terminal of the driver amplifier and the input terminal of the carrier amplifier project to each other when the second substrate is stacked on the first substrate. An electrical length from the input terminal of the driver amplifier to an output terminal of the carrier amplifier is set to a phase of (2n+1)×π, where n is an integer greater than or equal to 0.

A Doherty amplifier includes a divider configured to divide an input signal into two signals, a first amplifier configured to amplify one of the two signals and output the amplified signal to a first node, a second amplifier configured to amplify the other of the two signals and output the amplified signal to a second node, a balun including lumped parameter elements and configured to output a signal obtained by combining the signal output from the first amplifier with the signal output from the second amplifier to a third node, and a path configured to DC-connect the first node to the second node, with the third node therebetween.

An amplifier module includes a module substrate and first and second power transistor dies. The first power transistor die is coupled to a mounting surface of the module substrate, and has first and second input/output (I/O) contact pads and a first ground contact pad, all of which are all exposed at a surface of the first power transistor die that faces toward the mounting surface of the module substrate. The second power transistor die also is coupled to the mounting surface, and has third and fourth I/O contact pads and a second ground contact pad. The third and fourth I/O contact pads are exposed at a surface of the second power transistor die that faces away from the mounting surface of the module substrate, and the second ground contact pad is exposed at a surface of the second power transistor die that faces toward the mounting surface.

A radio frequency front-end is disclosed having a first power amplifier (PA) having a first PA input and a first PA output, a second PA having a second PA input and a second PA output, and a low-noise amplifier (LNA) having an LNA output connected to a receive output terminal and an LNA input. An input 90° hybrid coupler has a first port input connected to a transmit terminal, a second port input connected to a fixed voltage node through an isolation impedance, a third port output connected to the first amplifier input and a fourth port output connected to the second amplifier input. An output 90° hybrid coupler has a first port output connected to a common terminal, a second port output connected to the LNA input, a third port input connected to the second PA output, and a fourth port input connected to the first PA output.

Apparatus and methods for quadrature combined Doherty amplifiers are provided herein. In certain embodiments, a separator is used to separate a radio frequency (RF) input signal into a plurality of input signal components that are amplified by a pair of Doherty amplifiers operating in quadrature. Additionally, a combiner is used to combine a plurality of output signal components generated by the pair of Doherty amplifiers, thereby generating an RF output signal exhibiting quadrature balancing.

A power amplifier comprising: a first amplifier; a second amplifier, wherein the first and second amplifiers are arranged in parallel; an analogue pre-distortion network; a first coupler; and a second coupler, wherein the first coupler is configured to receive an input signal, direct said input signal to the first amplifier, and direct a first pre-distortion signal to the analogue pre-distortion network, wherein the first pre-distortion signal comprises a first distortion component generated at the input of the first amplifier, and the analogue pre-distortion network is configured to receive the first pre-distortion signal and manipulate its amplitude and/or phase to obtain a manipulated first pre-distortion signal, and the second coupler is configured to direct the manipulated first pre-distortion signal to the second amplifier.

An input signal is input to a main power amplifier and an auxiliary power amplifier. A combiner is connected to an output of the main power amplifier and an output of the auxiliary power amplifier. The combiner includes an impedance converter, first and second lumped elements. The impedance converter is connected to a combining point. The first lumped element is connected between the output of the main power amplifier and the combining point. The second lumped element is connected between the output of the auxiliary power amplifier and the combining point. A line length between the output of the main power amplifier and the combining point is the same as that between a line length between the output of the auxiliary power amplifier and the combining point.

A semiconductor device package includes a plurality of input leads and an output lead, a plurality of transistor amplifier dies having inputs respectively coupled to the plurality of input leads, and a combination circuit configured to combine output signals received from the plurality of transistor amplifier dies and output a combined signal to the output lead.

A semiconductor device package includes a plurality of input leads, a plurality of transistor amplifier dies having inputs respectively coupled to the plurality of input leads, and a combined output lead configured to combine output signals received from the plurality of transistor amplifier dies and output a combined signal.

A Doherty power amplifier and a device are disclosed. In a combiner of the Doherty power amplifier, a first input port and a termination port are open coupled by at least two coupled microstrip lines and/or a second input port and an output port are open coupled by at least two coupled microstrip lines. Therefore, a balanced amplitude bandwidth may be obtained and may be much broader than that of the existing solutions, in addition, a controllable size or a potentially small size may be realized. Furthermore, the Doherty power amplifier in this disclosure may provide large 2.sup.nd harmonic suppression to meet product spectrum mask requirements.