Demystifying Envelope Tracking: Use for High-Efficiency Power Amplifiers for 4G and Beyond

The efficiency of a radio-frequency (RF) power amplifier (PA) is generally defined as the ratio between the desired transmitted radio power and the total power from a power supply, which is rather low in average with modern high peak-to-average-power-ratio (PAPR) signals, as illustrated in Figure 1(a). Consequently, a small improvement in the efficiency of the RF PA can have substantial benefits for a wireless system and cut the overall costs of system operations.

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