A Comprehensive Survey on RF Energy Harvesting: Applications and Performance Determinants

\ua9 2022 by the authors. Licensee MDPI, Basel, Switzerland.There has been an explosion in research focused on Internet of Things (IoT) devices in recent years, with a broad range of use cases in different domains ranging from industrial automation to business analytics. Being battery-powered, these small devices are expected to last for extended periods (i.e., in some instances up to tens of years) to ensure network longevity and data streams with the required temporal and spatial granularity. It becomes even more critical when IoT devices are installed within a harsh environment where battery replacement/charging is both costly and labour intensive. Recent developments in the energy harvesting paradigm have significantly contributed towards mitigating this critical energy issue by incorporating the renewable energy potentially available within any environment in which a sensor network is deployed. Radio Frequency (RF) energy harvesting is one of the promising approaches being investigated in the research community to address this challenge, conducted by harvesting energy from the incident radio waves from both ambient and dedicated radio sources. A limited number of studies are available covering the state of the art related to specific research topics in this space, but there is a gap in the consolidation of domain knowledge associated with the factors influencing the performance of RF power harvesting systems. Moreover, a number of topics and research challenges affecting the performance of RF harvesting systems are still unreported, which deserve special attention. To this end, this article starts by providing an overview of the different application domains of RF power harvesting outlining their performance requirements and summarizing the RF power harvesting techniques with their associated power densities. It then comprehensively surveys the available literature on the horizons that affect the performance of RF energy harvesting, taking into account the evaluation metrics, power propagation models, rectenna architectures, and MAC protocols for RF energy harvesting. Finally, it summarizes the available literature associated with RF powered networks and highlights the limitations, challenges, and future research directions by synthesizing the research efforts in the field of RF energy harvesting to progress research in this area

RF Energy Harvesting For Self Powered Sensor Platform

This work demonstrates a RE powered sensor platform where energy can be available either in ambient FM band or emitted from a dedicated RF source. We realized the requirement with a dedicated chip built for RF power harvesting and conditioning A switched capacitor based ultra low power DC-DC boost converter is designed in 130nm CMOS technology as energy harvesting circuitry for ambient RF. The on-chip RE-DC resulted in a maximum efficiency of 44% with 9.75k Omega resistive load. At input sensitivities of -16dBm over 8 dominant frequencies, the sensor platform with strain gauge as sensor advertised a BEE packet every 20 minutes. For dedicated emitted radiations, the designed hybrid system is powered using sub-1 GHz frequencies. The resulting system has an end-to-end system efficiency of 9.1% and packet transmission interval of 90 seconds