Digitally Supply-Modulated GaN PAs with Analog Predistortion for Broadband Signals

Most next-generation communication standards, including 5G, feature increased instantaneous bandwidths, higher carrier frequencies, and noise-like signals. At the same time, the demands on transmitters in terms of efficiency and reconfigurability increase. In this contribution we will present supply-modulated GaN MMIC amplifiers at X and K band designed with those challenges in mind. Efficient digitally-driven multi-level supply modulators are used to enhance efficiency of the PAs with reduced-bandwidth tracking. The resulting nonlinearities are addressed with analog linearization concepts which do not require knowledge of the digital baseband, suitable for repeater applications.