摘要

A minimum pulse reservation method is proposed to reduce the switching frequencies of the supply modulated power amplifier (PA). It is achieved by expanding the minimum pulse length of the multi-level supply voltage. Also, by comparing the maximum voltage of the minimum pulse with the designed chopped voltage, the minimum pulse is reserved in an optimised way to maximise the PA efficiency. To validate the proposed technique, a four-level supply modulated PA is fabricated, which is excited by a wideband modulated signal, that is 40-MHz long-term evolution signal. Experimental results show that the proposed method can significantly reduce the switching frequencies and achieve higher efficiency than state-of-the-art bandwidth reduction methods, which is very promising for the wideband supply modulated PA design.

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