Enhancing RF-to-DC conversion efficiency of wideband RF energy harvesters using multi-tone optimization technique

Abstract

In this paper, a 1.8–2.6 GHz wideband rectenna is designed for radio frequency (RF) energy harvesting in the context of wireless sensor nodes (WSN). To assess the feasibility of ambient RF energy harvesting, the power density from RF base stations is analyzed through statistical measurements. Power density measurements are also performed close to Wi-Fi routers. Using these results, a methodology based on impedance matching network adaptation and maximum power transfer is proposed to design the wideband RF harvester. Using this method, three RF bands,i.e.GSM1800, UMTS and WLAN, are covered. The theoretical analysis is confirmed by simulations and measurements. From measurements results, the prototype RF-to-DC conversion efficiency is 15% at −20 dBm from 1.8 to 2.6 GHz. It is shown that with three RF sources in the chosen bands, each emitting at 10 dBm, the RF-to-DC conversion efficiency is 15% better compared to that measured with a single RF source. Finally, 7 µW is harvested at 50 m from a GSM1800 and UMTS base station. This value confirms the RF harvester workability to supply small sensors.

Design and implementation of a dual band bioinspired leaf rectenna for RF energy harvesting applications

“…Since Li et al 46 has two parallel rectifiers and the outputs of these rectifiers are not combined, efficiency values are given for each arm separately as 9.1% @ 0.9 GHz, 8.9% @ 2 GHz, which means that it has the minimum efficiency. On the other hand, Kuhn et al 47,48 have the same rate of efficiency values within 15%. Wang et al 49 has the minimum efficiency value, nearly 10% and proposed system has the nearly 13%.…”

“…Wang et al 49 has the minimum efficiency value, nearly 10% and proposed system has the nearly 13%. However, Kuhn et al 47,48 have the diverse type of working mechanisms such as multiband 47 or wideband 48 …”

Radio Frequency Energy Harvesting Sources

“…The past two decades have witnessed spectacular growth of mobile phone (cellular) communications, and there are currently in excess of 7.3 billion mobile phone subscribers in the world [51]. The expansion of cellular phone networks entails an increase in base stations.…”

A Compact Circular Rectenna for RF-Energy Harvesting at ISM Band

“…A simple stub-matching rectifier circuit is investigated for high conversion efficiency and impedance matching with low input power density. The measured data show that the prototype rectenna provides a high efficiency of 64% at input 0 dBm and output DC 1.5 V. The authors of [16] describe a broadband energy harvesting rectenna which has been proposed for WSN application in the frequency band ranging from 1.8 GHz to 2.6 GHz. To improve the performance of the rectifier, an optimization method has been developed, based on which a prototype rectenna is generated to cover GSM1800, UMTS, and Wi-Fi bands.…”