ALEX MOUAPI - Academia.edu (original) (raw)

Papers by ALEX MOUAPI

2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting

The output voltage of the Rectifying Antennas (Rectennas) is known to be very low, so Multi-Stage... more The output voltage of the Rectifying Antennas (Rectennas) is known to be very low, so Multi-Stage Voltage-Doubler (MSVD) rectifiers are the most considered solution for raising this voltage level. However, in the rectenna design, it is also necessary to consider the conversion efficiency. This paper proposes an analysis of the MSVD for a compromise between the DC output voltage and the conversion efficiency of the Rectenna. Up to ten stage voltage doubler have been studied in this paper, and their performance have been evaluated through the definition of a Rectifier Figure of Merit (RFoM). The result obtained shows the existence of an optimal number of stages of the MSVD for a given RF input power level. This paper suggests that the search for the optimal number of stages should be integrated into the design issues of an MSVD.

2020 IEEE International Conference on Environment and Electrical Engineering and 2020 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe)

In most research works, radiofrequency energy converter circuits are characterized by only their ... more In most research works, radiofrequency energy converter circuits are characterized by only their output DC voltage level and their conversion efficiency. These two characteristics are defined for a constant RF input power level. This work proposes a characterization of the performance of a rectifying antenna (rectenna) under non-static operating conditions. A rectenna design method is intended for the harvesting of ambient RF energy. The ambient power density levels in the 2.4 GHz bands are measured and reported in this work. A rectenna optimized to achieve optimal performance at the average detected power is proposed. Unlike previous work, the rectenna is characterized in terms of output DC voltage, conversion efficiency, and the Battery Recharging Time (BRT). It is also evaluated the performance of a Wireless Sensor Node (WSN) powered by the proposed rectenna. An average signal power of -1.55 dBm is obtained, and considering a mesh type network, it is obtained that a WSN can transmit data of a size of 4 kbits at more than 150 m based on the detected ambient power.

2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting

Voltage Doubler (VD) rectifiers are known to be most effective in the design of radiofrequency en... more Voltage Doubler (VD) rectifiers are known to be most effective in the design of radiofrequency energy harvesting circuits (known as rectenna for Rectifying Antenna). The performance comparisons in most of the previous work have been evaluated concerning single-wave or double-wave bridge rectifiers. However, there are several topologies of VD; this paper then proposes to compare the performance of two types of VD: the Latour VD (LVD) and the Schenkel VD (SVD). Both prototypes are designed with Schottky HSMS 2850 diode, and performances in terms of DC output voltage, conversion efficiency, and matching loss are evaluated. For operating frequencies between 0 and 3.5 GHz, it appears that the performance in terms of DC output voltage and conversion efficiency is almost similar. However, for matching losses, gaps of up to 60muW/Omega60\ \mu W/\Omega60muW/Omega are observed between the two types of VD. This difference can be significant if we consider the level of power consumed in most rectennas applications. The LVD is the topology that shows the least matching loss for input power between −20 dBm and 20 dBm.

2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting

The voltage-doubler (VD) rectifier circuits are the most used in the rectennas design. In this pa... more The voltage-doubler (VD) rectifier circuits are the most used in the rectennas design. In this paper, a method of designing a highly efficient Schenkel VD is proposed. The choice of the rectifying diode is first established according to measurements of ambient power density carried over in the literature. By using the filter Design tool of the Advanced Design System (ADS) software, a band-pass filter is designed to ensure a good power transfer between the antenna and the rectifier circuit. The filter elements are then optimized by the gradient method search to achieve optimum performance in the GSM band. Especially for a power density of 39 nW/cm2, the designed circuit associated with a 10 dBi gain antenna shows a conversion efficiency of 55%.

2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017

In this paper, a miniature RECtifying antENNA (rectenna) operating in the GSM band is designed an... more In this paper, a miniature RECtifying antENNA (rectenna) operating in the GSM band is designed and realized. The RF micro-generator consists of a simple rectifier circuit combined with a dipole antenna. The miniaturization of the circuit lies in avoiding the adaptation input filter and in optimizing the transmission lines by the gradient method search. The designed circuit is based on a Schenkel voltage doubler rectifier and Schottky diodes HSMS 2850 of AVAGO and is optimized through electromagnetic simulation software, Agilent ADS 2014 environment. Experimental results show an RF-DC conversion efficiency up to 40% with an output DC voltage of 1.8 V at 10 dBm of input power. A Wireless Power Transmission (WPT) experience demonstrates an average voltage of 22 mV over a distance of 3 m.

2019 IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2019

The conversion of electromagnetic energy into DC electrical energy is increasingly considered as ... more The conversion of electromagnetic energy into DC electrical energy is increasingly considered as the most appropriate solution to overcome the energy dependence of wireless sensor nodes (WSN). However, due to RF exposure limits, the output voltage levels reached are generally low. To amplify this voltage, the use of multi-stage voltage doubler (MSVD) rectifiers is the solution proposed by most designers. Nevertheless, it is recalled that in addition to the supply voltage, the effective of a WSN also depends on the harvested power by the conversion circuit; this issue is not very often dealt with in the design of the MSVDs. In this paper, it is proposed an analysis of the MSVDs to define how beneficial it to amplify the DC voltage without degrading the output power level of the conversion circuit. To consider these two performance criteria, a Rectifier Figure of Merit (RFoM) is defined. The results obtained through simulations with the Advanced Design System (ADS) software demonstrate the existence of an optimum number of stages that is linked to the RF power level incident. As a result of this observation, a relationship between the incident RF power and the optimal number of stages of the MSVD is established in this paper.

2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, 2020

Multistage Voltage Doubler Rectifiers (MVDR) are known to increase the level of the output DC vol... more Multistage Voltage Doubler Rectifiers (MVDR) are known to increase the level of the output DC voltage of a Rectifying Antenna (rectenna). However, the RF / DC conversion efficiency is very sensitive to the internal electrical characteristics of the used diode. This paper then proposes an analysis of the performance of an MVDR according to the features of the Schottky diode. A Rectenna Figure of Merit (RFoM), considering the DC output voltage as well as the RF / DC conversion efficiency, is defined to analyze MVDRs with up to ten stages. This analysis makes it possible to obtain that the most effective rectifier diode differs depending on the number of stages of the rectifier. More specifically, it is observed that, for two stages, the most efficient diode is the Schottky diode HSMS2820. For MVDR with more than five stages, the SMS 7630 diode is more suitable for low input power levels (less than 5 dBm). It is also observed that, for power levels higher than 5 dBm, the HSMS2850 diode offers the best compromise in terms of output DC voltage and conversion efficiency.

2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, 2020

Radiofrequency waves are increasingly seen as a promising solution for powering Wireless Sensor N... more Radiofrequency waves are increasingly seen as a promising solution for powering Wireless Sensor Nodes (WSN) dedicated to the Internet of Things (IoT) applications. However, by considering the RF source as a WSN power solution, Battery Recharging Time (BRT) becomes a critical performance metric, especially when the Quality of Service (QoS) is a requirement. In the literature, very few works propose an analysis of BRT based on an RF Energy Harvesting system. In this paper, the characterization of the BRT as a function of the harvestable power is analyzed, and modeling of the BRT is then proposed. The results are based on the ambient power density level measured in a building. It is obtained that the BRT undergoes as the received ambient power, a large scale fading effect shadowing more specifically the lognormal Shadowing.

Ce travail s'inscrit a la suite de ceux qui ont ete developpes ces dernieres annees dans le b... more Ce travail s'inscrit a la suite de ceux qui ont ete developpes ces dernieres annees dans le but de recycler de l 'energie disponible dans notre environnement pour alimenter les appareils electroniques de faible puissance. Particulierement, une alimentation autonome pour les noeuds d'un reseau de capteur sans fil destine aux operations de surveillance dans les trains est proposee. Deux approches de solution ont ete envisagees. Dans un premier temps, l'energie des vibrations mecaniques presentes dans le train en fonctionnement est convertie en energie electrique via un transducteur piezoelectrique. A cet effet, une poutre de type cantilever de frequence naturelle 15Hz correspondant a la frequence principale des vibrations detectees dans le train est concue et fabriquee. En associant a la poutre le composite QP20W de Mide Technology, une tension alternative d'amplitude 1,56 V est obtenue en circuit ouvert ainsi qu'une puissance recuperee de 6,3 ,uW atteinte pour...

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

In the field of rectifying antenna (rectenna) design, most of the proposed circuits are optimized... more In the field of rectifying antenna (rectenna) design, most of the proposed circuits are optimized for a fixed value of RF input power. However, this optimization does not take care to adjust the output characteristics of the rectenna to match environment propagation condition variability. This paper performs an evaluation of the performance of an RF/DC converter, dedicated to RF energy harvesting in complex environments. The random behavior of the amount of recoverable energy is taken into account by the selectivity of the conversion system. A judicious choice of the rectifying diode, as well as the rectifier topology, is made according to the level of the input power. The comparison criteria are the DC output voltage and the conversion efficiency. The obtained results show that the topology of a Single Series Diode (SSD) based on a Schottky diode SMS 7630 is the most efficient circuit for low input power levels below −45 dBm. Whereas for high power levels between 13 dBm and 18 dBm,...

2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, 2019

Given the low density of the surrounding RF powers, the rectifying stage is the one on which the ... more Given the low density of the surrounding RF powers, the rectifying stage is the one on which the designers of the rectenna (rectifying antenna) carry the most attention. Rectifier circuits must be of high efficiency to have usable DC output powers. Since the conversion efficiency is directly related to the electrical parameters of the used rectifying diode, this paper proposes a comparative study of the RF/DC conversion efficiency of an RF rectifier for the commonly considered Schottky diodes. In addition to the electrical parameters of the used diode, the operating frequency, as well as the desired level of DC output voltage, are considered in the comparison. Five diodes manufactured by AVAGO (HSMS 2820, HSMS 2850, HSMS 2860) and two Skyworks diodes (SMS 7621 and SMS 7630) are treated in this paper. This study will then provide designers with useful information in the selection of the rectifier diode and associated design parameters.

Applied Sciences, 2020

The vibrations, due to their abundance in most industrial processes, constitute an attractive sol... more The vibrations, due to their abundance in most industrial processes, constitute an attractive solution for the power supply of Industrial Wireless Sensor (IWS). However, the amount of energy that can be harvested presents numerous fluctuations due to the engines’ different operating modes (overload, full load, or even operation without charge). Most designs do not incorporate this fluctuation in the definition of the specifications of the autonomous IWS. This paper then presents a design method to ensure the node’s energy autonomy while maximizing its Quality of Service (QoS). To precisely define the specifications of the IWS, vibration measurements were carried out at its location for one month. The recorded data was used to propose a new Predictor of the Harvestable Energy from Vibrations (PHEV). A comparative evaluation of the proposed PHEV performances with a state-of-the-art predictor is carried out. The results obtained show that the PHEV makes it possible to minimize the Root...

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

Wireless Sensor Networks (WSNs) powered by an Energy Harvesting (EH) system, known as EH-WSN are ... more Wireless Sensor Networks (WSNs) powered by an Energy Harvesting (EH) system, known as EH-WSN are increasingly seen as the appropriate monitoring medium for environments for which, wired connections can be troublesome. This is, for example, the case of the vehicles in which many sensors are increasingly incorporated, thus resulting in a significant number of wired connections. In this paper, the vibrational-powered vehicle's sensors, through piezoelectric transducers is considered. The design method presented here is to enslave the sensor node to the amount of the extracted energy from mechanical vibrations. The piezoelectric transducer is modeled with Simscape tool of Matlab/Simulink software. The characteristics of vibrations detected in a vehicle are used as simulation parameters. The energy budget of a sensor node is quantified and used to evaluate the performance of the autonomous WSN. The range of the WSN is used as a performance metric. A maximum distance of 327 m is obtained for two sensor nodes which exchange information every 10 min. This is a promising result that can be applied in Vehicular Adhoc NETwork (VANET) to improve driving safety.

2018 IEEE International Conference on Environment and Electrical Engineering and 2018 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2018

In this paper, a method of designing highly efficient miniature rectenna (rectifying antenna) is ... more In this paper, a method of designing highly efficient miniature rectenna (rectifying antenna) is proposed. The design method is based on a judicious choice of the rectifying diode. Depending on the electrical internal elements of a Schottky diode, the RF/DC conversion efficiency is defined, and, by comparing four commonly used diodes, the HSMS 2850 diode manufactured by AVAGO demonstrates having the best conversion efficiency in the ISM band centralized at 2.45 GHz. A rectifier circuit based on a Latour voltage doubler is then designed. The designed rectifier is optimized to achieve good performance at 2.45 GHz. The simulated results are validated experimentally, and an RF/DC conversion efficiency of 27 % is achieved at 10 dBm of input power without the use of the RF matching filter. A satisfactory output DC voltage level of 1. 3 VVV capable of powering most of the radio modules of the currently marketed sensor nodes is also achieved.

2020 IEEE International Conference on Environment and Electrical Engineering and 2020 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2020

2019 IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2019

A sparaginase (ASNase), an enzyme biotechnologically produced by bacteria, is one of the most imp... more A sparaginase (ASNase), an enzyme biotechnologically produced by bacteria, is one of the most important compounds in polychemotherapy to treat acute lymphoblastic leukemia (ALL) in children. There are only three options available as medicine: native enzyme from Erwinia chrysanthemi (ErA) or extracted from Escherichia coli (EcA) and formulated as native or PEGylated (PEG-EcA). However, these options yet present some problems in patients, such as to elicit hypersensitivity and allergenic reactions, neurotoxicity, and hyperammonemia. Aiming to avoid some of these problems, our research group has developed several different mutant proteoforms, expressed in bacteria and yeast, in periplasmic or secreted to extracellular space; with improvement in specific activity, kinetic parameters and stability; different oligomerization states, glycosylated or not, through engineering of genes from E. coli, E. chrysanthemi and S. cerevisiae. We obtained mutants from E. coli ASNase more resistant to human proteases and less immunogenic. In relation to E. chrysanthemi enzyme, our mutants present higher asparaginase activity than the native form, with improved kcat. In addition, we obtained strains of Pichia pastoris that express glycosylated ASNases from bacteria. Last but noteworthy, we obtained P. pastoris and E. coli strains that express active ASNases from S. cerevisiae, an eukaryotic promising options to replace bacterial formulations. Biography Gisele Monteiro has completed her PhD at the University of São Paulo in Molecular Biology. Currently, she is an Associate Professor of Pharmaceutical Biotechnology in the Faculty of Pharmaceutical Sciences (FCF/USP) and the Vice-Coordinator of the Graduate Course in Biochemical-Pharmaceutical Technology. She has published more than 20 papers in reputed journals and has been serving as an Associate Editor of Brazilian Journal of Microbiology. She received 10 scientific awards, national and international. Her main scientific interest is the study of antitumor drugs and the engineering of proteins used as biopharmaceuticals, such as asparaginase.

Energies, 2019

This paper will present a complete discussion in recent design strategies for harvesting vibratio... more This paper will present a complete discussion in recent design strategies for harvesting vibration energy using piezoelectric cantilever transducers. The interest in this primary energy source is due to its presence in non-negligible quantities in most of the engines used in the industrial process. Previous work has shown that it is possible to harvest significant amounts of energy capable of supplying a wireless sensor (WS) node. However, in most research, only one step of the energy conversion and utilization chain is studied. Starting from the definition of the different design issues for a piezoelectric micro generator (PMG), the leading optimization solutions will be reviewed in this paper. Based on the findings, the quantification of the data transmission range of wireless sensor nodes powered by a PMG is proposed to support the objectives envisioned by Industry 4.0. The vibration characteristics taken from mining locomotives that have not yet been treated previously are used ...

ICT Express, 2018

In trying to reach the goal of controlling the environment, recent years have seen the rapid emer... more In trying to reach the goal of controlling the environment, recent years have seen the rapid emergence of Wireless Sensors Networks (WSN). Nevertheless, the lifetime of sensor nodes shows a strong dependence on battery capacity. Recently energy harvesting techniques have been considered to allow the use of WSN in the "deploy and forget" mode. This paper proposes an assessment of the performance of a WSN enslaved to an optimized Radiofrequency Energy Harvesting System (REHS). The energy budget of a sensor node in a Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol is quantified and used to evaluate the performance of the WSN.