In a Doherty amplifier including a carrier amplifier (6) and a peaking amplifier (8) connected in parallel with each other, a compensation circuit (9) for causing an impedance seen from an output end (9a) of the compensation circuit (9) toward the peaking amplifier (8) to be open within a used frequency range and compensating for frequency dependence of an impedance seen from an output of a combiner (10) toward the combiner (10) in a state in which the peaking amplifier (8) is not operating is arranged between the peaking amplifier (8) and the combiner (10). This achieves a wider bandwidth without making the circuit larger in size and more complicated.

A 3-stage Doherty amplifier that includes a three-way splitter, a carrier amplifier, first to second peak amplifiers, and an output combiner is disclosed. The output combiner includes first to fifth transmission lines with a /4 electrical length except for that in a downstream of the second peak amplifier, which provides a /2 electrical length. By dividing the latter transmission line into two parts each having a /4 length, and setting impedance thereof in a relation of (Z.sub.1/Z.sub.3).sup.2(Z.sub.L/3), the output impedance of the respective amplifiers are common to each other to be Z.sub.o, where Z.sub.1, Z.sub.3, and Z.sub.L are impedance of the transmission liens in respective downstream sides of the amplifiers, that of the transmission line provided in the output, and the load impedance, respectively.

A power amplifier circuit includes: a first differential amplifier that amplifies a first signal split from the input signal and outputs a second signal; a second differential amplifier that amplifies a third signal split from the input signal and outputs a fourth signal; a first transformer including a first input-side winding to which the second signal is input and a first output-side winding; a second transformer including a second input-side winding to which the fourth signal is input and a second output-side winding; a first phase conversion element that is connected in parallel with the first output-side winding and outputs a fifth signal; and a second phase conversion element that is connected in parallel with the second output-side winding and outputs a sixth signal. The first and second output-side windings are connected in series and output a signal obtained by adding voltages of the fifth and sixth signals together.

Power amplification system is disclosed. A power amplification system can include a Class-E push-pull amplifier including a transformer balun. The power amplification can further include a reactance compensation circuit coupled to the transformer balun. In some embodiments, the reactance compensation circuit is configured to reduce variation over frequency of a fundamental load impedance of the power amplification system.

Power amplification system is disclosed. A power amplification system can include a Class-E push-pull amplifier including a transformer balun. The power amplification can further include a reactance compensation circuit coupled to the transformer balun. In some embodiments, the reactance compensation circuit is configured to reduce variation over frequency of a fundamental load impedance of the power amplification system.

Embodiments of a multiple-path amplifier (e.g., a Doherty amplifier) and a module housing the amplifier include a first amplifier (or first power transistor die) with a first output terminal, a second amplifier (or second power transistor die) with a second output terminal, and an impedance inverter line assembly electrically connected between the first and second output terminals. The impedance inverter line assembly includes a first transmission line and a surface mount component connected in series between the first and second output terminals. In various embodiments, the surface mount component is selected from a fixed-value capacitor, a fixed-value inductor, a tunable capacitor, a tunable inductor, and a tunable passive component network.

A power amplification device comprises an amplifying unit and a combining unit. The amplifying unit is provided with a plurality of groups of amplifier circuits that amplifies the power of a radio frequency signal. The plurality of groups of amplifier circuits each includes a predetermined number of the amplifier circuits. The combining unit includes a plurality of combiners. The amplifying unit is housed by a first housing and the combining unit is housed by a second housing which is separate from the first housing. The amplifying unit is configured to be attachable to and detachable from the combining unit. The amplifying unit is configurable by one or more control voltages to perform amplification in classes AB, B and/or C. The amplification in classes AB, B, and/or C is compatible with a type of the combiner.

A power amplification device comprises an amplifying unit and a combining unit. The amplifying unit is provided with a plurality of groups of amplifier circuits that amplifies the power of a radio frequency signal. The plurality of groups of amplifier circuits each includes a predetermined number of the amplifier circuits. The combining unit includes a plurality of combiners. The amplifying unit is housed by a first housing and the combining unit is housed by a second housing which is separate from the first housing. The amplifying unit is configured to be attachable to and detachable from the combining unit. The amplifying unit is configurable by one or more control voltages to perform amplification in classes AB, B and/or C. The amplification in classes AB, B, and/or C is compatible with a type of the combiner.

An amplification unit contains two or more sets containing a plurality of amplification circuits, and amplifies power of an RF (Radio Frequency) signal. A combining unit contains two or more combiners corresponding to the two or more sets, combines RF signals output by the amplification circuits, and outputs a resultant RF signal. The amplification unit and the combining unit have two or more connectors which are arranged transversely. The amplification unit and the combining unit are attachable/detachable.

An amplification unit contains two or more sets containing a plurality of amplification circuits, and amplifies power of an RF (Radio Frequency) signal. A combining unit contains two or more combiners corresponding to the two or more sets, combines RF signals output by the amplification circuits, and outputs a resultant RF signal. The amplification unit and the combining unit have two or more connectors which are arranged transversely. The amplification unit and the combining unit are attachable/detachable.