@ARTICLE {9556,
author={A. Boaventura and A.C.  Collado and N.B.C. Carvalho and A. G. Georgiadis},
doi={10.1109/TMTT.2014.2300452},
journal={IEEE Transactions on Microwave Theory and Techniques},
title={Spatial Power Combining of Multi-Sine Signals for Wireless Power Transmission  applications},
year={2014},
month={April},
volume={62},
number={4},
pages={1022-1030},
ISSN={0018-9480}
}