Measurement method using radio frequency power amplifier

A measurement method, comprising:

• applying a first gate bias voltage to a gate terminal of a first transistor that is included in a radio frequency (RF) power amplifier during a direct current (DC) measurement period, wherein the first transistor operates in a linear operation mode during the DC measurement period;
• measuring a first drain-source voltage between a drain terminal and a source terminal of the first transistor and a current flowing through the first transistor via a connection node during the DC measurement period;
• determining a resistance value of the first transistor based on the first drain-source voltage and the current flowing through the first transistor;
• applying a second gate bias voltage and a drain bias voltage to a gate terminal and a drain terminal of a second transistor, respectively, wherein the second transistor is included in the RF power amplifier and a source terminal of the second transistor is electrically connected to the drain terminal of the first transistor via the connection node;
• and
• measuring a DC value of the second transistor via the connection node during the DC measurement period,
• wherein the first transistor operates in a saturation operation mode during a RF stress period or a RF measurement period, measuring the DC value of the second transistor comprises measuring a current-voltage (IV) characteristic curve of the second transistor, and the drain bias voltage that is applied to the drain terminal of the second transistor depends on the resistance value of the first transistor and the current flowing through the first transistor,
• wherein measuring the IV characteristic curve of the second comprises:
• sweeping at least one of the second gate bias voltage or the drain bias voltage in a voltage range having a plurality of step voltages;
• measuring step currents corresponding to the plurality of step voltages via the connection node;
• and
• generating the IV characteristic curve based on the step currents and the plurality of step voltages.