Prof. Dr. Alfrêdo Gomes Neto
Instituto Federal de Paraiba, Av. Primeiro de Maio, 720 - Jaguaribe, João Pessoa 58015-435, PB, Brazil
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Academic Career Length
31Years (1996-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications7 June 2021 in IEEE Access
Journal Article
LFLeidiane C. M. M. Fontoura
Leidiane C. M. M. FontouraHLHertz Wilton De Castro Lins
Hertz Wilton De Castro LinsABArthur S. Bertuleza
Arthur S. BertulezaADAdaildo Dassuncao
Adaildo DassuncaoAlfrêdo Gomes NetoThis paper presents the synthesis of multiband frequency selective surfaces (FSSs) using supervised machine learning (ML) with the decision tree (DT) algorithm. The proposed FSS structure is composed of an array of metallic patches printed on a dielectric substrate for stopband spatial filtering microwave applications. The shapes of the metallic patches are based on the sunflower (helianthus annus) geometry. In the first step, a parametric analysis is performed to investigate the use of different FSS geometries, including those with circular, annular and corolla integrated patch elements, to compose the sunflower geometry, regarding multiband and polarization independent performances with size reduction. Two bioinspired FSS geometries are synthesized using supervised machine learning with the decision tree algorithm. The random forest (RF) algorithm is used to validate the decision tree algorithm and to confirm the obtained results. The numerical analysis of the proposed FSS geometries is performed using Ansoft Designer software. Prototypes are fabricated and measured. The good agreement observed between simulated and measured results has validated the proposed approach. The use of supervised machine learning with the decision tree algorithm resulted in a particularly efficient and accurate synthesis procedure due to its intuitive implementation and simplified and effective data analysis modelling.
9 April 2018 in IET Microwaves, Antennas & Propagation
Journal Article
DMDeisy Formiga Mamedes
Deisy Formiga Mamedes
Alfrêdo Gomes NetoJSJefferson Costa e Silva
Jefferson Costa e Silva
JBJens Bornemann
Jens Bornemann
Reconfigurable frequency‐selective surfaces (RFSSs) are of significant interest in applications, such as secure communication systems or tunable radomes, to improve indoor communication and smart antennas. In order to change the frequency‐selective surface (FSS) characteristics, and therefore its frequency response, conventional methods include loading with active semiconductor devices such as varactors, PIN diodes, Schottky diodes and radio‐frequency microelectromechanical system. Another possibility is the use of mechanical adjusts, such as spring resonators or mechanical rotation. When PIN diodes are used, commonly only the reverse and forward regions, OFF and ON states, respectively, are considered. In this study, the implementation of an RFSS is described, using PIN diodes as active components. The RFSS is based on the four‐arms star geometry, and initial design equations and procedures are presented. Numerical and measured results are shown for different project stages, with a very good agreement. In addition to obtaining two distinct resonant frequencies, due to the OFF and ON states, a third situation is included, considering the PIN diode threshold region when the FSS becomes practically transparent, which is an interesting feature with potential applications.
1 December 2013 in Journal of Microwaves, Optoelectronics and Electromagnetic Applications
Journal Article
FSFrancisco Carlos Gurgel da Silva Segundo
Francisco Carlos Gurgel da Silva Segundo
ACAntonio Luiz Pereira de Siqueira Campos
Antonio Luiz Pereira de Siqueira CamposAlfrêdo Gomes NetoJournal Article
Alfrêdo Gomes NetoJSJefferson Costa Silva
Jefferson Costa SilvaJCJoabson Nogueira de Carvalho
Joabson Nogueira de CarvalhoCPCustodio Peixeiro
Custodio PeixeiroA review on planar printed structures that are based on Matryoshka-like geometries is presented. These structures use the well-known principle of Matryoshka dolls that are successively nested inside each other. The well-known advantages of the planar printed technology and of the meandered nested Matryoshka geometries are combined to generate miniaturized, multi-resonance, and/or wideband configurations. Both metal and complementary slot structures are considered. Closed and open configurations were analyzed. The working principles were explored in order to obtain physical insight into their behavior. Low-cost and single-layer applications as frequency-selective surfaces, filters, antennas, and sensors, in the microwave frequency region, were reviewed. Potential future research perspectives and new applications are then discussed.
13 March 2019 in IEEE Antennas and Wireless Propagation Letters
Journal Article
ESErik Farias da Silva
Erik Farias da SilvaAlfrêdo Gomes NetoCPCustodio Peixeiro
Custodio Peixeiro1 June 2020 in Journal of Microwaves, Optoelectronics and Electromagnetic Applications
Journal Article
FSFrancisco Ary Alves de Souza
Francisco Ary Alves de SouzaACAntonio Luiz Pereira de Siqueira Campos
Antonio Luiz Pereira de Siqueira CamposAlfrêdo Gomes Neto
ALEXANDRE SERRESCACamila Albuquerque
Camila AlbuquerqueThis work proposes the application of a slot in the ground plane, Defected Ground Structure (DGS), of a microstrip patch antenna. The application of this technique aims to attenuate higher-order excited modes without deteriorating the antenna parameters in the fundamental mode. The methodology for the design of the slot in H-format is presented, based on the physical dimensions of the microstrip patch antenna. The positioning of the DGS concerning the feed line was determined from a detailed parametric analysis. The antenna was designed for the fundamental mode at 2.45 GHz frequency. Two antenna prototypes were built, with and without DGS, and measurements of reflection coefficient, gain, and radiation pattern were performed. The measured results show that the application of DGS considerably attenuated higher-order excited modes. A good agreement between simulated and measured results is achieved.
About Me
Alfredo Gomes Neto was born in João Pessoa, PB, Brazil. He received B.Sc., M.Sc., and D.Sc. degrees, all in Electrical Engineering and in Microwave Areas, from the Federal University of Paraiba, Campina Grande, Brazil, in 1986, 1989, and 1994, respectively. In 1993, he developed part of his D.Sc. at the ENSEEIHT, Institut National Polytechnique de Toulouse, Toulouse, France, to where he returned in 2005, during his post-doctorate research. Since 1989, he has been with the Federal Institute of Paraiba (IFPB), Joao Pessoa, PB, Brazil. In 1994, he was one of the founders of the Telecommunications and Applied Electromagnetism Group (GTEMA) at the IFPB. He was the General-Chair of the Brazilian Microwave Symposium in 2000, and General-Chair of the MOMAG 2012, the most important Brazilian microwave and optoelectronics conference. From 2015 to 2019, he served as a co-advisor professor in the doctoral program at Instituto Superior Técnico, Lisbon, Portugal. He has more than 190 papers published in journals, conferences, etc. His research interests include electromagnetic theory, microwaves, wave propagation, frequency-selective surfaces, filters, sensors, antennas, and numerical methods. Dr. Gomes Neto is a member of the Brazilian Society of Microwaves and Optoelectronics, SBMO, and senior member of the Institute of Electrical and Electronics Engineers, IEEE. He has served as a reviewer for several journals and conferences.