Power amplifier circuit and radio frequency system

A radio frequency system, comprising:

• a power amplifier circuit, comprising:
• a power amplifier unit, comprising:
• a signal input port;
• a signal output port;
• a power transistor comprising a first end, a second end, and a third end, wherein the first end of the power transistor is grounded, and the second end of the power transistor is connected to the signal input port;
• and
• a first inductor comprising a first end and a second end, wherein the first end of the first inductor is connected to the third end of the power transistor and the second end of the first inductor is connected to the signal output port;
• and
• a broadband improvement unit;
• a radio frequency antenna configured to transmit a radio frequency signal which is amplified by the power amplifier circuit;
• and
• a power supply configured to supply power to the power amplifier circuit,
• wherein
• the signal input port is configured to receive radio frequency signals in a plurality of frequency bands,
• the power transistor is configured to perform power amplification on the radio frequency signals in the plurality of frequency bands,
• the signal output port is configured to output the radio frequency signals that are in the plurality of frequency bands and on which power amplification is performed,
• the broadband improvement unit is configured to adjust a parallel resonance frequency of the power amplifier unit to reduce envelope impedance of the power amplifier unit between a first target frequency and a second target frequency,
• the first target frequency is a maximum frequency difference between the plurality of frequency bands, and
• the second target frequency is a minimum frequency difference between the plurality of frequency bands.

A power amplifier circuit, comprising:

• a power amplifier unit, comprising:
• a signal input port;
• a signal output port;
• a power transistor comprising a first end, a second end, and a third end, wherein the first end of the power transistor is grounded, and the second end of the power transistor is connected to the signal input port;
• and
• a first inductor comprising a first end and a second end, wherein the first end of the first inductor is connected to the third end of the power transistor and the second end of the first inductor is connected to the signal output port;
• and
• a broadband improvement unit, comprising:
• a decoupling capacitor comprising a first end and a second end, wherein the first end of the decoupling capacitor is grounded;
• a second inductor comprising a first end and a second end, wherein the first end of the second inductor is connected to the second end of the decoupling capacitor;
• intermediary circuitry connected to the second end of the second inductor, the intermediary circuity comprising a radio frequency capacitor connected to ground and a first resistor;
• and
• a third inductor comprising a first end and a second end, wherein the first end of the third inductor is connected to the first resistor, and the second end of the third inductor is connected to the first inductor.