Power Amplifier Implementation Challenges in Front-Ends for 5G mobile Broadband

In the last years, although the 5G specs are not ready yet, we have seen an evolution on the architecture definition of the 5G systems, especially in the Sub-6GHz bands. It is clear that the mMIMO structures are one of the adopted paths to follow. Although the PA maximum output power was reduced in these multi-antenna systems to comply with the radiated power limits, this does not mean that the challenges are smaller. To name a few, following the system partitioning, the analog front-ends (AFE) demand dramatically increased, imposing different difficulties to the RF design community. The reduced space to accommodate all the TRX systems and consequently the AFE blocks for all the antennas, strongly limits the design freedom, thus, a higher level of integration is advisable. In addition, green technologies are demanded for the new 5G systems, so the PA still needs to be highly efficient. However, having a reduced absolute power, the traditional complex DPD systems cannot be used, meaning that now more than ever before, the PA architecture choice needs to be in line with the digital resources available for the digital pre-correction so that the system power efficiency is optimized. In this talk, these and other topics will be addressed