Single-Chip GaN X-Band MMIC Dynamic Supply PAs

This paper discusses a fully integrated single- chip supply-modulated power amplifier (SM-PA) GaN PA for amplifying high peak-to-average power ratio (PAPR) signals at X-band carrier frequencies. Components of the MMIC are detailed. Specifically, 10-W MMIC GaN PAs with greater than 60% efficiency at 10GHz with efficient GaN supply modulators consisting of a 100-MHz switching dc-dc converter and a cascode UHF PA, for signals with envelope bandwidths of several 100 MHz and PAPR up to 10dB, are detailed. Other transmitter approaches for high PAPR broadband signals, such as outphasing transmitters and PAs with output harmonic injection are overviewed in the context of supply modulation, and the main technical challenges are discussed.