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. 2017 Jul 28;17(8):1732.
doi: 10.3390/s17081732.

A Long-Distance RF-Powered Sensor Node with Adaptive Power Management for IoT Applications

Matteo Pizzotti  1   2 , Luca Perilli  3 , Massimo Del Prete  4 , Davide Fabbri  5 , Roberto Canegallo  6 , Michele Dini  7 , Diego Masotti  8 , Alessandra Costanzo  9   10 , Eleonora Franchi Scarselli  11   12 , Aldo Romani  13   14
Affiliations

A Long-Distance RF-Powered Sensor Node with Adaptive Power Management for IoT Applications

Matteo Pizzotti et al. Sensors (Basel). .

Abstract

We present a self-sustained battery-less multi-sensor platform with RF harvesting capability down to -17 dBm and implementing a standard DASH7 wireless communication interface. The node operates at distances up to 17 m from a 2 W UHF carrier. RF power transfer allows operation when common energy scavenging sources (e.g., sun, heat, etc.) are not available, while the DASH7 communication protocol makes it fully compatible with a standard IoT infrastructure. An optimized energy-harvesting module has been designed, including a rectifying antenna (rectenna) and an integrated nano-power DC/DC converter performing maximum-power-point-tracking (MPPT). A nonlinear/electromagnetic co-design procedure is adopted to design the rectenna, which is optimized to operate at ultra-low power levels. An ultra-low power microcontroller controls on-board sensors and wireless protocol, to adapt the power consumption to the available detected power by changing wake-up policies. As a result, adaptive behavior can be observed in the designed platform, to the extent that the transmission data rate is dynamically determined by RF power. Among the novel features of the system, we highlight the use of nano-power energy harvesting, the implementation of specific hardware/software wake-up policies, optimized algorithms for best sampling rate implementation, and adaptive behavior by the node based on the power received.

Keywords: RF power transfer; adaptive power management; energy harvesting; nano-power DC/DC converter; rectifying antenna; ultra-low power sensor node; wireless sensor networks.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
General scheme of the overall system.
Figure 2
Figure 2
Rectenna prototype with highlighted different sections.
Figure 3
Figure 3
PIFA-like antenna performance: (a) reflection coefficient and (b) E and H-fieldradiation pattern at 868 MHz.
Figure 4
Figure 4
Rectifying section performance: (a) matching network and rectifier schematic topologies and (b) RF-to-dc conversion efficiency and output dc voltage versus input poweravailable.
Figure 5
Figure 5
Measured and simulated rectified power for different link distances.
Figure 6
Figure 6
DC/DC low-power converter block diagram.
Figure 7
Figure 7
DC/DC efficiency vs. open circuit input voltage.
Figure 8
Figure 8
Harvesting module board.
Figure 9
Figure 9
Block diagram of the sensing node.
Figure 10
Figure 10
Schematic, not to scale, of the node current consumption in off-mode; the average charge consumption in each activation phase is Q=I*T=4.7 mA*680 ms=3.196 mC.
Figure 11
Figure 11
Schematic, not to scale, of the node current consumption in standby-mode; the average charge consumption in each activation phase following the power on phase is Q=I*T=3.81 mA*38 ms ~ 145 μC.
Figure 12
Figure 12
Sensing node and harvesting module boards.
Figure 13
Figure 13
Schematic of the harvesting module and its interface with the active node.
Figure 14
Figure 14
Transmission period vs. Extracted currents in different operating modes.
Figure 15
Figure 15
Power extracted vs. Node distance.
Figure 16
Figure 16
Transmission data rate and policy relationship with node distance.
Figure 17
Figure 17
Combined graph showing the relationship between distance, extracted power and transmission periods.
Figure 18
Figure 18
Voltage drop and control signals of micro-controller in off-mode (a) and standby-mode (b).
Figure 19
Figure 19
Data received format.
Figure 20
Figure 20
Power optimization circuits and policy detection waveforms.
See this image and copyright information in PMC

References

    1. Yick J., Mukherjee B., Ghosal D. Wireless sensor network survey. Comput. Netw. 2008;52:2292–2330. doi: 10.1016/j.comnet.2008.04.002. - DOI
    1. Sudevalayam S., Kulkarni P. Energy harvesting sensor nodes: Survey and implications. IEEE Commun. Surv. Tutor. 2011;13:443–461. doi: 10.1109/SURV.2011.060710.00094. - DOI
    1. Del Prete M., Masotti D., Costanzo A., Magno M., Benini L. A 2.4 GHz–868 MHz dual-band wake-up radio for wireless sensor network and IoT; Proceedings of the IEEE 11th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob); Abu Dhabi, UAE. 19–21 October 2015; pp. 322–328.
    1. Vullers R.J.M., van Schaijk R., Doms I., van Hoof C., Mertens R. Micropower energy harvesting. Solid-State Electron. 2009;53:684–693. doi: 10.1016/j.sse.2008.12.011. - DOI
    1. Lu X., Wang P., Niyato D., Kim D.I., Han Z. Wireless networks with RF energy harvesting: A contemporary survey. IEEE Commun. Surv. Tutor. 2015;17:757–789. doi: 10.1109/COMST.2014.2368999. - DOI

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