Electromagnetic Energy Harvesting

Abstract

Energy harvesting is the process of extracting energy from external sources (e.g. thermal energy, solar energy, wind energy etc). The process of “electromagnetic energy harvesting” in particular, harvests energy from ambient electromagnetic waves. Owing to the ubiquity of electromagnetic waves in the present era, this offers an effective, real time, portable, low power energy source that can lessen our dependence on rechargeable batteries. Electromagnetic energy harvesting enables energy recycling by employing three subsystems. Firstly, we have the receiving antenna, with maximized power capturing capability. This antenna then feeds energy to the rectification subsystem, which converts the high frequency AC signal into DC. Last is the storage subsystem, which stores the harvested energy, and then provides a continuous voltage output. The storage system also acts as a backup, once the real time harvested energy is insufficient. In this EM harvesting approach, energy has been harvested from multiple frequency bands, namely GSM 900, GSM 1800 and ISM band. Secondly, multiple element Microstrip patch antennas have been designed that maximize captured energy. For the rectification part, charge pumps have been utilized that both rectify and up convert the RF signal. For the storage subsystem, super capacitors with enhanced storage capacity, have been employed.