Multi-level LINC transmitter with nonisolated power combiner

By using a non-isolated power combiner, the overall power efficiency can be improved by reducing the wasted power at the combined out-phased signal. To further improve the efficiency of the low-power mode, a multi-power mode out-phasing power amplifier (PA) is proposed with load modulation by switches. Compared with the conventional linear amplification using nonlinear component (LINC) transmitter, the proposed multi-level LINC improves the power-added-efficiency more than 40% for a 7 dB peak-to-average power ratio orthogonal frequency division multiplexing signal. To the authors´ knowledge, the proposed LINC PA is the first multi-level LINC PA without multiple power supplies.