Static and Dynamic Error Vector Magnitude Behavior of 2.4-GHz Power Amplifier

This paper presents error vector magnitude (EVM) behavior under two different modes of a reference voltage (V_ref); one is a static EVM with a constant V_ref and the other is a dynamic EVM with a pulsed Vref. A 2.4-GHz two-stage power amplifier (PA) is implemented by GaAs HBT technology to investigate EVM behavior for IEEE 802.11 g wireless local area network application. A square wave pulse with the duty cycle of 50% is applied as V_ref for dynamic operation mode. In this paper, it is shown that a dynamic EVM is worse than a static EVM because a transient response of PA output distorts preamble and signal in orthogonal frequency division multiplexing signal bursts. This transient response is explained by a two-pole thermal network in this study, and transient response experiments with a resistor-capacitor (R-C) network at a power supply were performed for verification