Operational range and energy harvesting efficiency are important characteristics of a passive receiver. The power received by a rectification diode-based energy harvesting device as a function of distance, with respect to the EH signal transmitter, and type of transmitted waveform is illustrated in FIG. 2. It is seen that, for a desired received power level, the operational distance may be optimized by properly selecting the number of tones for a power optimized waveform (POW).
The efficiency of a rectification diode-based energy harvesting receiver as a function of the received signal power and the type of received signal is illustrated in FIG. 3A. As illustrated in FIG. 3A, the highest level of RF to direct current (RF-to-DC) conversion efficiency is achieved with a chaotic signal. The peak-to-average power ratio (PAPR) of various test signals as a function of complementary cumulative distribution function (CCDF) of the envelope of the test signal is shown in FIG. 3B, which illustrates that a chaotic signal delivers the highest PAPR.
FIG. 4 illustrates three different receiver configurations for receiving an information-bearing signal and retrieving the information from the signal while also harvesting energy from the signal. In an example, the information reception requirement of an information receiver that is collocated with an energy harvesting device may be satisfied by an appropriate power split, time split, or antenna separation, as illustrated in FIG. 4.
