PROJECT TITLE :

A 65% efficient envelope tracking radio-frequency power amplifier for orthogonal frequency division multiplex

ABSTRACT:

A high-efficiency radio-frequency (RF) power amplifier (PA) is described for high peak-to-average power ratio (PAPR) orthogonal frequency division multiplexed signals. Envelope tracking is used, where the supply voltage of an RF amplifier is modulated in harmony with the envelope of the RF signal. The envelope modulator is a split-frequency style composed of a switched mode power supply (SMPS) for the low-frequency content, and a hybrid amplifier for the high-frequency half. The hybrid amplifier combines digital switching with a linear amplifier during a transformer coupled push-pull structure. For verification, a 7 dB PAPR 3 MHz bandwidth third generation partnership project long-term evolution (LTE) signal is employed. When amplifying the AC part of the LTE envelope signal, fifty six.2% potency is achieved by the hybrid amplifier at four.six W output power into a ten Ω load. Combined with a 94.4% economical SMPS, the modulator can produce twenty three.4 W at eighty three% efficiency. This is combined with an eighty.threepercent economical three hundred MHz RF PA. Along they achieved 65.6% DC-to-RF potency at 18.a pair of W RF output power. The measured PAPR at the amplifier output was six.five dB.