Hybrid Silicon-GaAs PA for MIMO Applications

This paper introduces the design techniques for a family of Wi-Fi PA with a new approach based on maximally reducing the GaAs MMIC area and resizing it with external integrated components. This paper proposes the development of a set PA for the integrated front-end module (FEM) of 802.11a/b/g/n and in the near future for 802.16d/e. In the multi-mode concept, a technological partition called the "stripped" PA has been adopted to minimize the overall manufacturing cost without impacting the performance of the PA. In particular the PA MMIC cell, manufactured in a commercial InGaP/GaAs technology, has been reduced to minimum size and complexity keeping the performances level at the highest standards currently available. Results on both a standard linear PA design approach used for a SISO system and vehicle for the validation of the approach and on a more challenging architecture which aims to enable the MIMO configuration through a dramatic increase in efficiency adopting a smart-biasing system plus the benefit of the digital pre-distortion are presented. These approaches combine to provide performance such as PAE comparable with the state of the art SISO and MIMO PAs, while meeting the stringent requirements like EVM required by standard and specifications