@INPROCEEDINGS {28267,
author={R.  Correia and N.B.C. Carvalho},
doi={},
booktitle={IEEE Wireless Power Transfer Conf. - WPTC},
title={Backscatter radio coverage enhancements using improved WPT signal waveform},
year={2015},
month={May},
volume={-},
pages={1-4} 
}