A High-Efficiency RF Harvester with Maximum Power Point Tracking

This paper presents the implementation of a high-efficiency radiofrequency (RF) harvester, which consists of a rectenna and a maximum power point tracker (MPPT). The rectenna was characterized from -30 dBm to -10 dBm at 808 MHz, achieving an efficiency higher than 60% at -10 dBm. Experimental results also show that the rectenna can be well modelled as a Thévenin equivalent circuit, which allows the use of a simple ensuing MPPT. The complete RF harvester was tested, achieving an overall efficiency near 50% at -10 dBm. Further tests were performed powering a sensor node from a nearby antenna.Peer ReviewedPostprint (published version

Harvesting Ultra-Low Power Wireless Signals in the GHz Range

We present methods for harvesting wireless energy as low as -30 dBm (1uW) from the 2.4 GHz frequency range (e.g. WiFi signals) with discrete components. We have constructed a proof-of-concept device which is capable of operating at -18.8 dBm (13.2 uW) with no onboard power sources, relying solely on the 2.4 GHz energy source. The device is constructed on a PCB and consists of an impedance matching network, a rectifier, and a DC-DC converter. The impedance matching network matches a 2.4 GHz 50 Ohm input source to the high impedance rectifier and provides a passive boost. The rectifier converts the AC signal from the impedance matching network to a DC signal. This DC signal feeds into the DC-DC converter subsystem which boosts the voltage from about 45 mV DC to a clean 95 mV DC output

3.3V DC Output At-16dBm Sensitivity And 77% PCE Rectifier For RF Energy Harvesting

This paper presents a high voltage conversion at high sensitivity RF energy harvesting system for IoT applications. The harvesting system comprises bulk-to-source (BTMOS) differential-drive based rectifier to produce a high efficiency RF energy harvesting system. Low-pass upward impedance matching network is applied at the rectifier input to increase the sensitivity and output voltage. Dual-oxide-thickness transistors are used in the rectifier circuit to maintain the power efficiency at each stage of the rectifier. The system is designed using 0.18μm Silterra RF in deep n-well process technology and achieves 4.07V output at -16dBm sensitivity without the need of complex auxiliary control circuit and DC-DC charge-pump circuit. The system is targeted for urban environment

Energy Resources in Agriculture and Forestry: How to be Prepared for the Internet of Things (IoT) Revolution

The Internet of Things (IoT) revolution is getting attention of all kinds of enterprises and industries: from the big ones to the startups. From the energy point of view, deploying IoT devices in urban or industrial environments is not a dramatic problem since electrical outlets and chemical batteries are easily available almost everywhere. However, why not tap into natural resources first? The future may bring an Internet of Natural Things (IoNaT). If so, the agricultural and forestry industries will certainly take advantage of such technology. The question will then be how to power the IoNaT. Chemical batteries are not an environment-friendly option in an agricultural field or in a forest. In this chapter, we suggest different and innovative, natural and easily available energy sources and the main processes to harvest them. The use of these natural and revolutionary technologies may ensure that monitored data could be obtained in a sustainable way