A radio frequency (RF) summer circuit having a characteristic impedance Z.sub.0 comprises first and second ports coupled by first and second resistances, respectively, to a junction. The circuit further comprises a series combination of a third resistance and a switch movable between open and closed positions and an amplifier having input and output terminals and operable in an off state and an on state wherein the series combination is coupled across the input and output terminals of the amplifier between the junction and a third port. The first resistance, second resistance, and the third resistance are all substantially equal to Z.sub.0/3. Further, when the switch is moved to the closed position and the amplifier is switched to the off state a passive mode of operation is implemented and when the switch is moved to the open position and the amplifier is switched to the on state an active mode of operation is implemented. The RF summer circuit develops a summed signal at the third port equal to a sum of signals at the first and second ports modified by one of first and second gain values.

A radio frequency (RF) summer circuit having a characteristic impedance Z.sub.0 comprises first and second ports coupled by first and second resistances, respectively, to a junction. The circuit further comprises a series combination of a third resistance and a switch movable between open and closed positions and an amplifier having input and output terminals and operable in an off state and an on state wherein the series combination is coupled across the input and output terminals of the amplifier between the junction and a third port. The first resistance, second resistance, and the third resistance are all substantially equal to Z.sub.0/3. Further, when the switch is moved to the closed position and the amplifier is switched to the off state a passive mode of operation is implemented and when the switch is moved to the open position and the amplifier is switched to the on state an active mode of operation is implemented. The RF summer circuit develops a summed signal at the third port equal to a sum of signals at the first and second ports modified by one of first and second gain values.

Embodiments of the present disclosure include a harmonic power amplifying circuit with high efficiency and high bandwidth and a radio-frequency power amplifier. The circuit comprises an input matching network (11), a transistor (M), and an output matching network (12); a gate of the transistor (M) connected to an output end of the input matching network (11), a drain thereof connected to an input end of the output matching network (12), and a source thereof being grounded; wherein the output matching network (12) enables a lower sideband of the harmonic power amplifying circuit to work in a continuous inverse F amplification mode and an upper sideband of the harmonic power amplifying circuit to work in a continuous F amplification mode; wherein the output matching network (12) and a parasitic network of the transistor (M) form a low pass filter. By transitioning from the continuous inverse F power amplifier working mode to the continuous F power amplifier working mode, the efficiency of a continuous harmonic control power amplifier is effectively improved to be higher than 60%, a relative bandwidth is improved to be higher than 80%, and the harmonic impedance is simple to match and easy to realize.

A power amplifier circuit includes a power splitter, a first amplifier, a second amplifier, a third amplifier, a fourth amplifier, a first bias circuit, a first line connecting the first bias circuit and the first amplifier, and a second line connecting the first bias circuit and the third amplifier on the same semiconductor substrate, in which the first line and the second line are formed such that a voltage drop amount of the first bias voltage between the first bias circuit and the first amplifier is substantially equal to a voltage drop amount of the first bias voltage between the first bias circuit and the third amplifier.

An RF amplifier includes an amplifier input, a transistor die with a transistor and a transistor input terminal, a fundamental frequency impedance matching circuit coupled between the amplifier input and the transistor input terminal, and a harmonic frequency termination circuit coupled between the transistor input terminal and a ground reference node. The harmonic frequency termination circuit includes a first inductance coupled between the transistor input terminal and a first node, and a tank circuit coupled between the first node and the ground reference node. The tank circuit includes a first capacitance coupled between the first node and the ground reference node, and a second inductance coupled between the first node and the ground reference node. The tank circuit is configured to shunt signal energy at or near a second harmonic frequency, while appearing as an open circuit to signal energy at a fundamental frequency of operation of the RF amplifier.

A transmitter circuit is provided. The transmitter circuit has an input port, a first transmission node, a second transmission node, a third transmission node, and a fourth transmission node and includes a first operational amplifier, a first output stage, a first resistor-capacitor network, a first switch group coupled between the first resistor-capacitor network and the input port, a first impedance matching circuit coupled to the first output stage, the first transmission node, and the second transmission node, a second operational amplifier, a second output stage, a second resistor-capacitor network, a second switch group coupled between the second resistor-capacitor network and the input port, and a second impedance matching circuit coupled to the second output stage, the third transmission node, and the fourth transmission node.

A transmitter circuit is provided. The transmitter circuit has an input port, a first transmission node, a second transmission node, a third transmission node, and a fourth transmission node and includes a first operational amplifier, a first output stage, a first resistor-capacitor network, a first switch group coupled between the first resistor-capacitor network and the input port, a first impedance matching circuit coupled to the first output stage, the first transmission node, and the second transmission node, a second operational amplifier, a second output stage, a second resistor-capacitor network, a second switch group coupled between the second resistor-capacitor network and the input port, and a second impedance matching circuit coupled to the second output stage, the third transmission node, and the fourth transmission node.

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 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 power amplifier circuit includes an input-stage power amplifier configured to receive a radio-frequency input signal, an output-stage power amplifier configured to output an amplified radio-frequency output signal, and an intermediate-stage power amplifier disposed between the input-stage power amplifier and the output-stage power amplifier. The intermediate-stage power amplifier includes a first transistor, a second transistor, and a capacitor having a first end connected to an emitter of the first transistor and a second end connected to a collector of the second transistor. The intermediate-stage power amplifier receives a signal at a base of the second transistor thereof and outputs an amplified signal from a collector of the first transistor thereof.