Outphasing amplifier

An outphasing amplifier comprising:

• a first amplifier and a second amplifier;
• a synthesizer including a first transmission line, a second transmission line and a node,
• a first coupling circuit and a second coupling circuit each electromagnetically coupled to but not directly connected to the first transmission line and the second transmission line, respectively, and
• wherein:
• one end of the first transmission line is connected to an output terminal of the first amplifier,
• one end of the second transmission line is connected to an output terminal of the second amplifier,
• another end of the first transmission line and another end of the second transmission line are connected to the node,
• the first coupling circuit and the second coupling circuit are not directly connected to the synthesizer,
• each of the first and second coupling circuits comprises a coupling line and a stub connected to the coupling line,
• the stub of the first coupling circuit and the stub of the second coupling circuit are configured to contribute opposite reactance components to signals transmitted through the first and second transmission lines, respectively, and
• the first transmission line, second transmission line, first coupling circuit, and second coupling circuit are disposed on a common dielectric substrate.