Radio frequency energy harvesting has attracted considerable interest as a technique of enabling self-powered wireless networks. This technique faces several challenges, such as the receiving and the rectifying modules of a rectenna system. Multiband antennas provide several comparative advantages against the goal of maximizing the amount of energy harvesting. In this work, we present a multiband microstrip patch antenna with three slits operating in the LoRaWAN (Long Range Wide Area Network) and the cellular (GSM-1800 and UMTS) communication frequency bands. A feasible solution of the antenna is obtained by the application of a recently introduced nature-inspired optimization technique, namely the Coyote Optimization Algorithm. The proposed antenna operates satisfactorily in the LoRaWAN (Long Range Wide Area Network) and the cellular (GSM-1800 and UMTS) communication frequency bands. Measured results of the proposed antenna exhibit an acceptable performance (multiband frequency operation, maximum gain of 3.94 dBi, broadside operation) and demonstrate features of operation, which make it a strong candidate for various RF energy harvesting applications.

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Multiband Patch Antenna Design Using Nature-Inspired Optimization Method

ABSTRACT Radio Frequency Energy Harvesting is found to be the best alternative to conventional batteries for providing endless power to the sensor networks connected to perform various applications in the smart city. The electromagnetic energy density in the ambient environment is very low and not uniform, which demands a high gain multi-band rectenna system operating at mostly available energy bands and a suitable rectifier circuit that offers large PCE performance. This paper introduces a triple-band monopole rectenna with enhanced performance for smart city applications. A defective ground structure (DGS) has been investigated for a significant increase in gain with an increasing number of resonant frequencies. The proposed antenna operates over a band of frequencies that lies within 1.25–3 GHz, which covers 1.8/2.1/2.45 GHz frequencies. The antenna offers the gain values of 4.16/6.54/10.2 dB at 1.8/2.1/2.45 GHz frequencies, respectively. A single diode series-connected rectifier has been opted to efficiently operate over a wide range of input power levels from −10 dBm to 5 dBm and offers a minimum conversion efficiency of 60% within the operating bands at 0 dBm input power. The rectenna system is experimentally measured and the measured output voltage at 2.45 GHz frequency is 1.123 V.

A triple band rectenna for RF energy harvesting in smart city applications

This paper presents a reconfigurable band of operation from 5G to 4G for radio frequency energy harvesting (RF-EH) in the different wireless communication bands. The designed antenna with steerable beam pattern based on tunable of the graphene pads. The proposed antenna consists of printed CPW-fed circular monopole shaped and five rectangular strips are added with equally separation angle 45o. These strips are connected with monopole by using graphene pads. The monopole antenna resonates at 5G applications extended from 3 GHz up to 7.8 GHz at -10 dB reflection coefficient with Omni-radiation pattern over the operating band without any bias voltage of the graphene pads. By applying the dc voltage to the graphene pad the rectangular strips are connected to the monopole and the designed antenna start to resonant from 1.8 GHz to 7.5 GHz to add the 4G wireless applications. The steering of the beam from 60o to -60o according to the graphene pad that connect to the monopole. The graphene pad exhibits as variable resistance from almost short to open circuit with and without voltage bias, respectively. The designed antenna is simulated using High Frequency Structure Simulation (HFSS) Ansys ver. 19. The simulated equivalent circuit of the graphene is applied then reduced graphene oxide (RGO) pads are deposited to validate the results. Fabricated prototype is then used to experimentally validate the simulation results. Finally, Reflection coefficient and radiation pattern measurements and simulations are presented, good agreement between these results.

Frequency Reconfigurable and Radiation Pattern Steering of Monopole Antenna Based on Graphene Pads

Radio Frequency (RF) energy harvesting is a promising alternative for obtaining energy in the ambient environment. It aims to search for new sources of RF energy and components, to obtain a circuit with high efficiency for converting electromagnetic waves into direct current DC. In this paper, we provide a broad overview of the main blocks of RF energy harvesting such as transmit and receive antennas, impedance matching circuit and rectifier circuit. The parameters and components of these different blocks play a crucial role in achieving high RF-DC conversion efficiency. We present in detail these different blocks used to make RF energy harvesting to power electronic devices with low energy consumption.

Efficiency in RF energy harvesting systems: A comprehensive review

The future 6G and tactile internet (TI) paradigms pose challenges and demand for requirements that are far beyond what the 5G—today at its dawn—will ever achieve. The classical approaches in designing devices, systems and infrastructures will not be suitable to build the AI-driven (Artificial Intelligence) 6G network. This work envisages a critical part for MEMS/NEMS technologies in making 6G turn into reality. Such a leading role sits on a reformulation of the common concept of Hardware (HW) triggered by Micro/Nanotechnologies and Materials. To this end, the WEAF Mnecosystem, i.e. the Water, Earth, Air and Fire Micro/Nanotechnologies Ecosystem, is conceived, leveraging the analogy with the four classical elements in nature, and is explained in details in the following pages, along with the discussion of some reference examples. In a nutshell, Earth and Air are the classical concepts of HW and Software (SW), respectively. Water is the novel formulation of the concept of HW, which, like water, is liquid in terms of functional characteristics and gains, at the same time, some features typical of the SW (i.e. Air). Fire, eventually, is the HW devoted to harvest, store and transfer energy, raising its level of abstraction to the concept of heat, which flows from warmer to cooler bodies.

The WEAF Mnecosystem: a perspective of MEMS/NEMS technologies as pillars of future 6G, tactile internet and super-IoT

This paper presents multiband monopole antenna for radio frequency energy harvesting applications. The proposed antenna has good performance in wireless communication bands. The antenna is printed on FR4 substrate with matching L shaped stubs, to achieve suitable impedance bandwidth. Two symmetric stubs with width equal to 0.6 mm and five slot arms are etched on the radiator surface, each arm is responsible for certain resonant frequency. The antenna operates at five operating bands (GPS band, DSC band, ISM band, WiFi band and WiMax band) with reflection coefficients below — 10 dB. The simulation result of the rectifier demonstrate that are operating with Triple-band RF energy harvesting system for three bands wide-band at 2.5 GHz, 3.7 GHz and 5.8 GHz. This antenna shows good matching between simulation and experimental results. The proposed rectenna can provide high RF-DC conversion efficiency which is suitable for RF energy harvesting applications.

Multiband Coplanar Monopole Antenna for Energy Harvesting

This paper presents three resonant bands of microstrip monopole antenna for radio frequency energy harvesting applications. The proposed antenna has a good performance in GSM-900/1800 and GPS/UMTS bands. The rectifier circuit design consist of several rectifier branches to collect the largest amount of RF power, due to the non-linearity and the complex input impedance of the rectifying circuit, Therefore, an improved impedance matching technique is introduced which is aimed to improve the performance of the rectifier with a varying condition. The proposed antenna is printed on FR4 substrate with modified ground plane to achieve suitable impedance bandwidth. Two V shaped arms with optimized angle are integrated on the L shaped monopole radiator. Each arm is responsible for certain resonating frequency. The antenna operates at three frequency bands (GSM 900/1800, GPS and UMTS bands) with reflection coefficient below — 10 dB.

Hala Abed Elmonem Elsadek

Papers

Multiband Coplanar Monopole Antenna for Energy Harvesting

Tri-Band Microstrip Monopole Antenna for Energy Harvesting