Frequency Selective Surfaces as Reconfigurable Superstrate Applied to a Dipole Antenna for 5G NR

Abstract This paper introduces a novel reconfigurable superstrate using a band-stop frequency selective surface (FSS) based on four arms star geometry. The proposed reconfigurable superstrate is applied to a dipole antenna for use in 5G NR technology with a frequency of 3.545 GHz. The study includes both simulated and experimental results which confirm the redirection of the antenna radiation pattern. The developed structure exhibits radiation in only one half-space, high polarization isolation, and a redirection of the radiation pattern up to ±55°. The ideal cases were considered, where the ON and OFF states of the diodes were replaced by short circuits and gaps, respectively. Overall, the results demonstrate the effectiveness of the proposed FSS as a promising solution for 5G NR technology applications

Bio-Inspired Wearable Antennas

Due to the recent miniaturization of wireless devices, the use of wearable antennas is steadily increasing. A wearable antenna is intended to be a part of the clothing used for communication purposes. In this way, a lower visual cost may be achieved. Recently, biologically inspired design, a kind of design by cross-domain analogy is a promising paradigm for innovation as well as low visual cost. The shapes of the plants are structures optimized by nature with the primary goal of light energy capture, transforming it into chemical energy. In this case, they have similar behavior to that of parabolic reflectors; this enables microwave engineers design innovative antennas using bio-inspired concepts. One of the advantages of using bio-inspired plant shapes is the design of antennas with great perimeters in compact structures. Thus, we have small antennas operating in low frequencies. This chapter presents the recent development in bio-inspired wearable antennas, easily integrated to the clothes and accessories used by the body, built in denim, low-cost flexible dielectric, and polyamide flexible dielectric, that is flexible with high resistance to twists and temperatures, for wireless body area network (WBAN) applications, operating in cellular mobile (2G, 3G, and 4G) and wireless local area network (2.4 and 5 GHz) protocols

Bio-Inspired Microstrip Antenna

In the last few years, bio‐inspired solutions have attracted the attention of the scientific community. Several world‐renowned institutions have sponsored and created laboratories in order to understand the forms, functions and behavior of living organisms. Some methods can be highlighted in the search for geometric representation of the shapes found in the nature, the fractal geometry, the polar geometry, and the superformula of Gielis. This chapter is focusing on bio‐inspired microstrip antennas, especially on leaf‐shaped antennas from the Gielis superformula that open a vast research field for more compact antennas with low visual impact

Power Line Communication: Análise de Desempenho de uma Rede Doméstica com Adaptadores padrão homeplug AV / Power Line Communication: Performance Analysis of a Home Network with homeplug AV Adapters

With the increase in the number of Internet users, due to digital inclusion, it is necessary to find the best possible way to provide this service. Among all forms of data transmission, PLC (Power Line Communication) is the one that has stood out the most in recent years, mainly due to its infrastructure, which allows users in semi-urban or even rural regions, and by the fact of ensuring high speed rates (up to 200 Mbps), through the broadband PLC, the BPL (Broadband Power Line), which uses the HomePlug AV standard. However, because the infrastructure used is the power lines, PLC is subject to numerous problems, such as interference, noise and attenuation. Therefore, there is a need to evaluate the performance of this broadband technology with regard to its use in domestic environments, analyzing its effectiveness amidst electrical interference. This paper presents an analysis of the performance of a PLC network that uses the HomePlug AV standard, with the objective of evaluating its viability in a domestic environment, since it presents several challenges for this technologyEsde 

Fractal and Polar Microstrip Antennas and Arrays for Wireless Communications

This chapter presents the research done by authors in recent years on microstrip antennas and their applications in wireless sensors network. The subject is delimited to the study of conventional microstrip antennas, from which antennas with fractal and polar shapes are proposed. A detailed description of the antenna design methodology is presented for some prototypes of microstrip antennas manufactured with different dielectric substrates. Analysis of the proposed antennas has been done through computational simulation of full-wave methods. Experimental characterization of antennas and dielectric materials has been performed with the use of a vector network analyzer. The results obtained for the resonant and radiation parameters of the antennas are presented. Computer-aided design (CAD) of microstrip antennas and arrays using fractal and polar geometrical transformations results in a wide class of antenna elements with desirable and unique characteristics, such as compact, exclusive, and esthetic antenna design for multiband or broadband frequency operation with stable radiation pattern

Application of the iterative method based on the concept of waves (WCIP) in the analysis of antennas and multilayer planar circuits.

Apresentam-se neste trabalho a modelagem e a análise de circuitos planares multicamadas para altas frequências utilizando um método iterativo baseado no conceito de ondas (Wave Concept Iterative Procedure – WCIP). A formulação adotada no método permite determinar uma relação simples entre ondas incidentes e ondas refletidas em diferentes meios dielétricos dos dois lados de uma descontinuidade, através de uma combinação linear dos campos eletromagnéticos. O tratamento dos fenômenos eletromagnéticos é formulado em dois domínios. A reflexão é tratada no domínio modal e o espalhamento definido, a partir das condições de contorno e de continuidade, no domínio espacial. A propagação dos campos em um guia de ondas permite a aplicação da Transformada de Fourier e a decomposição da onda nos modos TE e TM. A transformada de Fourier em modos (Fourier Modal Transform – FMT) é a ferramenta fundamental no processo iterativo WCIP, uma vez que ela permite realizar a transformação entre os domínios. Um primeiro tratamento matemático apresentado para a formulação permite a simulação de circuitos planares com uma camada. Em seguida, essa formulação é expandida para a análise de circuitos planares multicamadas. Os resultados obtidos com o programa desenvolvido em MATLAB, para simular circuitos planares multicamadas (filtro e antena patch alimentada através uma fenda), são comparados com resultados experimentais de medição e simulados apresentados na literatura especializada. Por fim, estruturas de combinadores espaciais de potência quase-ópticos são apresentadas bem como a formulação de uma estrutura amplificadora multicamadas baseada nos conceitos destes. Os polarizadores são colocados perpendicularmente na entrada e na saída da estrutura com um elemento ativo para a amplificação. Os polarizadores são considerados ideais e desenvolvidos com o WCIP. Uma impedância negativa é utilizada para a amplificação. A utilização do método das fontes auxiliares permite a modelagem eletromagnética da estrutura composta por elementos passivos e elementos ativos.This work presents the modeling and analysis of multilayer planar circuits for frequencies of a few GHz using an iterative method based on the wave concept (Wave Concept Iterative Procedure – WCIP). This method determines a simple relation between the incident and reflected waves in different media of each side of a discontinuity. The treatment of the field electromagnetic phenomena is formulated in two domains. The reflection is treated in the modal domain and the diffraction, defined from the continuity and boundaries conditions, in the space domain. A consideration of the fields’ propagation in a rectangular wave guide allows the application of a Fourier Transform and wave decomposition into TE and TM modes. A Fourier Modal Transform (FMT) is the basic tool in the iterative procedure; it allows to carry out the transformation between the two modes. An initial mathematical formulation is presented to allow the simulation of planar circuits. Finally, this formulation is expanded for multilayer planar circuits. Simulation results with the developed method for planar circuits and multilayer planar circuits (filter and slot coupled patch antenna) have been compared with measured and simulated results found in the literature. Finally, quasi-optical space power combining circuits are presented as well as multilayer amplifier structure based on the quasi-optical circuits concepts. Polarizers are placed perpendicularly between the input and the output of the structure and an active element for the amplification. The polarizers are considered as ideal and developed with the WCIP. Negative impedance is used for the amplification. The use of the auxiliary source method allows an electromagnetic modeling of the composed structure for passive and active elements

ANALYSIS OF A SIMPLE AND MULTILAYER FSS WITH A BIO-INSPIRED ELEMENT FOR WLAN APPLICATIONS

<p>This article aims to present a single and multilayer Frequency Selective Surface (FSS) with bio-inspired element geometry, with filtering capability (blocking/rejection) to the 2.4 GHz WLAN frequency band. </p&gt

Classification of Partial Discharge Sources in Ultra-High Frequency Using Signal Conditioning Circuit Phase-Resolved Partial Discharges and Machine Learning

This work presents a methodology for the generation and classification of phase-resolved partial discharge (PRPD) patterns based on the use of a printed UHF monopole antenna and signal conditioning circuit to reduce hardware requirements. For this purpose, the envelope detection technique was applied. In addition, test objects such as a hydrogenerator bar, dielectric discs with internal cavities in an oil cell, a potential transformer and tip–tip electrodes immersed in oil were used to generate partial discharge (PD) signals. To detect and classify partial discharges, the standard IEC 60270 (2000) method was used as a reference. After the acquisition of conditioned UHF signals, a digital signal filtering threshold technique was used, and peaks of partial discharge envelope pulses were extracted. Feature selection techniques were used to classify the discharges and choose the best features to train machine learning algorithms, such as multilayer perceptron, support vector machine and decision tree algorithms. Accuracies greater than 84% were met, revealing the classification potential of the methodology proposed in this work.</p

Parametric Study of Printed Monopole Antenna Bioinspired on the Inga Marginata Leaves for UWB Applications

Abstract A microstrip leaf-shaped printed monopole antenna bioinspired on the Inga marginata leaves is presented in this paper for UWB applications. A parametric study of the proposed antenna bioinspired geometry was conducted in order to verify their resonant properties. The antenna was designed with a rectangular slitted ground plane for impedance matching and fabricated on inexpensive glass fiber substrate and fed by a 50 Ω microstrip line. Numerical and experimental results were obtained. The results show an impedance bandwidth superior to 10.26 GHz, greater than the bandwidth considered UWB (7.5 GHz). Antenna dimensions were optimized with the computer program Ansys Designer® used to simulate the electromagnetic behavior of the antennas by the method of moments

Bio-inspired Printed Monopole Antenna Applied to Partial Discharge Detection

A new, bio-inspired printed monopole antenna (PMA) model is applied to monitor partial discharge (PD) activity in high voltage insulating systems. An optimized sensor was obtained by designing a PMA in accordance with the characteristics of the electromagnetic signal produced by PD. An ultra-wideband (UWB) antenna was obtained by applying the truncated ground plane technique. The patch geometry was bio-inspired by that of the Inga Marginata leaf, resulting in a significant reduction in size. To verify the operating frequency and gain of the PMA, measurements were carried out in an anechoic chamber. The results show that the antenna operating bandwidth covers most of the frequency range of PD occurrence. Moreover, the antenna presented a good sensitivity (mean gain of 3.63 dBi). The antenna performance was evaluated through comparative results with the standard IEC 60270 method. For this purpose, simultaneous tests were carried out in a PD generator arrangement, composed by an oil cell with point-to-plane electrode configurations. The developed PMA can be classified as an optimized sensor for PD detection and suitable for substation application, since it is able to measure PD radiated signals with half the voltage levels obtained from the IEC method and is immune to corona discharges