Exploiting the Marx Generator as a 100 MHz High-Speed Multilevel Supply Modulator

This paper proposes a distinct topology based on a Marx generator circuit to realise a high-speed switching supply modulator for amplitude modulation. In order to achieve high modulation bandwidth the circuit complexity is kept low. Four voltage levels are generated where the base voltage level is separated from the other levels. This feature makes it possible to set the supply voltage around a specific operating point, while maintaining the opportunity to operate from a single voltage supply which makes this circuit very flexible. The feasibility of the proposed circuit is verified by designing and fabricating a prototype which is realised with a four-layer FR4 board and tested with a 10 W SiC MESFET power amplifier (PA). The measured overall average drain efficiency of up to 55% is demonstrated with a 4-ASK signal. The prototype capabilities are validated for different modulation bandwidths up to 100 MHz. To the authors best knowledge, this is the first time that a Marx generator circuit is used as a high-speed supply modulator.