Experimental Comparison of RF Waveform Designs for Wireless Power Transmission

The possibility to harvest energy from ambient
radio-frequency (RF) sources has intrigued humankind for the
past several decades. In this context, there has been a tremendously growing research interest in the field of wireless power
transfer (WPT) using the RF range of the electromagnetic
(EM) spectrum. In this paper, we experimentally investigate
the aspect of real-time energy harvesting (EH) via different
types of waveform designs such as orthogonal frequency division multiplexing (OFDM), square, triangular, sinusoidal, and
sawtooth. We make use of a Software Defined Radio (SDR)
and a Powercast P21XXCSR-EVB EH module to carry out
the experiments on the practical device to assess performance.
Specifically, we are interested in obtaining insights based on
the comparison between the aforementioned waveform designs
from the perspectives of the separation distance between the
USRP and P21XXCSR-EVB EH module, and power emission via
USRP. In this vein, some additional experiments are subsequently
performed after a suitable candidate waveform has been reported.
The demonstration of the EH is provided in terms of the abovementioned investigation metrics while seeking the best waveform
to support WPT.