On-Site and External Energy Harvesting in Underground Wireless

Abstract

Energy efficiency is vital for uninterrupted long-term operation of wireless underground communication nodes in the field of decision agriculture. In this paper, energy harvesting and wireless power transfer techniques are discussed with applications in underground wireless communications (UWC). Various external wireless power transfer techniques are explored. Moreover, key energy harvesting technologies are presented that utilize available energy sources in the field such as vibration, solar, and wind. In this regard, the Electromagnetic (EM)- and Magnetic Induction (MI)-based approaches are explained. Furthermore, the vibration-based energy harvesting models are reviewed as well. These energy harvesting approaches lead to design of an efficient wireless underground communication system to power underground nodes for prolonged field operation in decision agriculture.

Zenneck Waves in Decision Agriculture: An Empirical Verification and Application in EM-Based Underground Wireless Power Transfer

“…More details of the UG impulse response measurements are given in [21,65,75]. Field experiment in an outdoor Wireless Underground Sensor Network (WUSN) setup is not an easy task due to various challenges due to extreme climate and temperature [22,77,78]. Getting timely results of the experiments is very hard to achieve in an outdoor setting.…”

“…Generally, agriculture fields lack ambient RF energy sources, i.e., stray EM waves, which can be utilized to harvest energy for self-sustainable operation of sensor devices [22]. Another harvesting approach is to harvest energy from received communication signals.…”

“…Another harvesting approach is to harvest energy from received communication signals. Two approaches can be adopted for harvesting energy from communication signals: Time sharing and frequency sharing [22]. In time sharing, time slots are divided between the information transfer and RF energy transfer.…”

“…However, these can lower the performance of information communication and need new equipment, thus increasing the deployment cost. A rectenna is a specialized antenna used for energy harvesting which can be used for collection and rectification of the EM waves [22].…”

“…An antenna design with high-intensify Zenneck wave generation capability is of vital importance to enhance underground wireless power transfer efficiency. A rectenna is a specialized antenna used for power transfer which can be used for collection and rectification of the EM waves [22]. Additionally, other important parameter selections (e.g., waveform, transmit power, time and frequency domains) also need careful consideration [70].…”