Radio frequency power amplifier circuit

A radio frequency power amplifier circuit having an input terminal for receiving an input signal having an input power, and an output terminal for outputting an output signal having an output power larger than the input power, the radio frequency power amplifier circuit comprising:

• a first amplifier stage having a first input and a first output, a second amplifier stage having a second input and a second output, and a third amplifier stage having a third input and a third output, the respective first input, second input and third input being arranged to receive respective power fraction signals having respective power fractions of the input power, and the respective first output, second output and third output being electrically coupled to the output terminal for outputting respective output signals;
• and
• an input power splitter for providing the respective power fraction signals having the respective power fractions of the input power to the first, second and third inputs, the input power splitter comprising:
• a splitter input terminal electrically connected to the input terminal for receiving the input signal from the input terminal;
• a first input transmission line arranged between a first node and a second node and a second input transmission line arranged between a third node and a fourth node;
• an electrical reactive element having a first terminal electrically connected to both the second node and to the third node, and having a second terminal electrically coupled to the third input,
• the first node and the fourth node being electrically coupled to the first input and the second input, respectively, and the splitter input terminal being electrically coupled to the first terminal;
• a third input transmission line arranged between the splitter input terminal and the first node;
• and
• a fourth input transmission line arranged between the splitter input terminal and the fourth node,
• for electrically connecting the splitter input terminal to the first terminal via the first input transmission line and the third transmission line, and via the second transmission line and the fourth transmission line.

A radio frequency power amplifier circuit having an input terminal for receiving an input signal having an input power, and an output terminal for outputting an output signal having an output power larger than the input power, the radio frequency power amplifier circuit comprising:

• a first amplifier stage having a first input and a first output, a second amplifier stage having a second input and a second output, and a third amplifier stage having a third input and a third output, the respective first input, second input and third input being arranged to receive respective power fraction signals having respective power fractions of the input power, and the respective first output, second output and third output being electrically coupled to the output terminal for outputting respective output signals;
• and
• an input power splitter for providing the respective power fraction signals having the respective power fractions of the input power to the first, second and third inputs, the input power splitter comprising:
• a splitter input terminal electrically connected to the input terminal for receiving the input signal from the input terminal,
• a first input transmission line arranged between a first node and a second node and a second input transmission line arranged between a third node and a fourth node, and
• an electrical reactive element having a first terminal electrically connected to both the second node and to the third node, and having a second terminal electrically coupled to the third input, the electrical reactive element being a variable reactance diode,
• the first node and the fourth node being electrically coupled to the first input and the second input, respectively, and the splitter input terminal being electrically coupled to the first terminal.