Non-Uniform Electromagnetic Band Gap lattices: a rectenna application

The IoT (Internet of Things) paradigm coupled with the advances in cloud-based platforms have digitalized societies. A plethora of smart-enabled devices are connected to the internet via novel, long range and low power telecommunication protocols. Radio Frequency (RF) energy harvesting emerged as a sustainable and promising solution for powering wireless sensors exploiting ambient electromagnetic energy. This article proposes a dipole rectenna leveraging non-uniform EBG (Electromagnetic Band Gap) lattices the special attribute of which is to focus reflected waves to a pre-specified point proved to enhance rectenna’s performance. Gain exceeding 8dBs was achieved at the frequency of resonance i.e. 868MHz. Simulated Voc values at the open circuited terminals of the dipole reached a maximum of 1.76V/m for incident waves of circular polarization and electrical field intensity equal to 1V/m. A Matching Network (MN) was designed at 868MHz and connected between the antenna and the rectifier yielding, at the output of the rectifier, DC voltage even 0.94V and power, available at its input, reaching even at 68.6μW. The overall performance of the proposed rectenna was estimated via statistical analysis of DC voltages and power values received, over frequencies around 868MHz and for multiple directions of arrival (DoAs).

I. Introduction

Nowadays, experiencing the Fourth Industrial Revolution (FIR) era, with a large number of crucial sectors as security, asset tracking, health, agriculture etc to have been digitalized, we see the Internet of Things (IoT) and Machine to Machine (M2M) technologies to continue to spread rapidly and to penetrate every area of our lives. A typical IoT system encompasses Wireless Sensor Networks (WSNs) collecting data from remotely placed and controlled sensors. One of the major issues encountered in deploying WSNs is the limited lifetime of the sensors. In order to power sensors two solutions are plausible, batteries or renewable energies through harvesting solutions. A sustainable and eco-friendly approach is energy harvesting which can prolong sensors’ lifetime taking advantage of the ubiquitous energy sources, without need for periodical maintenance.