Theoretical Study of the Input Impedance and Electromagnetic Field Distribution of a Dipole Antenna Printed on an Electrical/Magnetic Uniaxial Anisotropic Substrate

The present work considers the investigation of the effects of both electrical and magnetic uniaxial anisotropies on the input impedance, resonant length, and fields distribution of a dipole printed on an anisotropic grounded substrate. In this study, the associated integral equation, based on the derivation of the Green's functions in the spectral domain, is numerically solved employing the method of moments. In order to validate the computing method and the evaluated calculation code, numerical results are compared with available data in the literature treating particular cases of electrical uniaxial anisotropy; reasonable agreements are reported. Novel results of the magnetic uniaxial anisotropy effects on the input impedance and the evaluated electromagnetic field are presented and discussed. This work will serve as a stepping stone for further works for a better understanding of the electromagnetic field behavior in complex anisotropic and bi-anisotropic media

Outdoor thermal comfort optimization through vegetation parameterization : species and tree layout

The optimization of outdoor thermal comfort has become the keystone to guarantee the healthy and comfortable use of outdoor spaces. This study aims to optimize the outdoor thermal comfort through vegetation parameterization in a boulevard located in Guelma city, Algeria during summertime. However, two main parameters were investigated, species and tree layout, through a numerical simulation. We first collected microclimate data of a sunny summer day. Second, we used real microclimate data in different simulations using the Envi-met atmospheric model. The findings reveal that Ficus Nitida is the most significant species to intercept solar radiation and provide shade over the day in Souidani Boudjemaa Boulevard, with a maximum reduction of Ta = 0.3 °C and UTCI = 2.6 °C at 13:00 p.m. Tree layout is a determining parameter in the creation of shaded paths, based on the quality of the shadows cast by the trees, namely, their size. Thereby, planting the washingtonia palm trees along the center of the boulevard is the best option to maximize the shaded area within the boulevard, with maximum reduction of Ta = 1.8 °C and UTCI = 3.5 °C at 16:00 p.m.https://www.mdpi.com/journal/sustainabilityMechanical and Aeronautical Engineerin

Analysis of the Effect of the Axial Anisotropy on the Characteristic Impedance of a Shielded Microstrip Line

In this work, we present an analytical study for the calculation of the characteristic impedance and the dispersion characteristics of the dominant hybrid mode in a complex-anisotropic-medium shielded microstrip line based on the Method of Moments (MoM) and the Galerkin's procedure in the spectral domain. The numerical results are found to be in good agreement with available isotropic experimental data reported in literature

A Compact Semi-Circular and Arc-Shaped Slot Antenna for Heterogeneous RF Front-Ends

In this paper, a new miniaturized compact dual-band microstrip slot antenna is presented. To achieve the dual-band characteristics, two adjunct partial arc-shaped small slots are joined to two main circular slots embedded in the ground of the antenna structure. With a reduced size of 30 × 28.5 × 0.8 mm3, the proposed antenna presents a dual-band characteristic. The design is optimized using a High Frequency Structure Simulator (HFSS) followed by experimental verifications. An impedance bandwidth, for S11 ≤ 10 dB, that covers the 1.8 GHz and 2.4 GHz bands is accomplished, which makes the proposed antenna basically suitable for hand-held devices and medical applications. More applications such as digital communication system (DCS) 1.71–1.88 GHz, personal communication services (PCS) 1.85–1.99 GHz, Universal and mobile telecommunications system UMTS 1.92–2.17 GHz, Bluetooth 2.4–2.5 GHz, and Wi-Fi 2.4–2.454 GHz, Industrial Scientific and Medical radio frequency (RF) band ISM-2.4 GHz, Wireless Local Area Network (WLAN-2.4) are possible by simply changing one of the geometrical antenna dimensions. The antenna is characterized by stable radiation patterns as well

Analysis of the combinatory effect of uniaxial ulectrical and magnetic anisotropy on the input impedance and mutual coupling of a printed dipole antenna

The main objective of this work is to investigate the combinatory effects of both uniaxial magnetic and electrical anisotropies on the input impedance, resonant length and the mutual coupling between two dipoles printed on an anisotropic grounded substrate. Three different configurations: broadside, collinear and echelon are considered for the coupling investigation. The study is based on the numerical solution of the integral equation using the method of moments through the mathematical derivation of the appropriate Green’s functions in the spectral domain. In order to validate the computing method and evaluated MatlabⓇ calculation code, numerical results are compared with available literature treating particular cases of uniaxial electrical anisotropy; good agreements are observed. New results of dipole structures printed on uniaxial magnetic anisotropic substrates are presented and discussed, with the investigation of the combined electrical and magnetic anisotropies effect on the input impedance and mutual coupling for different geometrical configurations. The combined uniaxial (electric and magnetic) anisotropies provide additional degrees of freedom for the input impedance control and coupling reduction.This work was supported in part by the Electronic Components and Systems (ECSEL) Joint Undertaking, which is part of the POSITION-II Project under Grant Ecsel-7831132- Position-II-2017-IA, www.position-2.eu, in part by Fundação para a Ciência e a Tecnologia-Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MCTES) through National Funds and co-funded European Union (EU) Funds under Project UIDB/50008/2020-UIDP/50008/2020, in part by the General Directorate of Scientific Research and Technological Development (DGRSDT)-Ministry of Higher Education and Scientific Research (MESRS), Algeria, and in part by the Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (MCIU/AEI-Agencia Estatal de Investigación- al Fondo Europeo de Desarrollo Regional (AEI/FEDER), UE) under Grant RTI2018-095499-B-C31

Low-Profile UWB-MIMO Antenna System with Enhanced Isolation Using Parasitic Elements and Metamaterial Integration

A new compact UWB multiple-input–multiple-output (MIMO) antenna is presented in this paper. The proposed antenna, with a compact size of 30 × 20 × 1.6 mm3, consists of a two-element microstrip line-fed pentagonal-shaped patch associated with a parasitic element and a partial ground plane. Three complementary split-ring resonator (CSRR) structures are integrated into the defected ground with the aims of reducing the mutual coupling and enhancing the bandwidth. A UWB impedance bandwidth is achieved covering the FCC band (3.1–10.6 GHz), corresponding to a reflection coefficient below −10 dB and a reduced mutual coupling below −22 dB. Additionally, acceptable limits of the diversity performance parameters are obtained. Furthermore, all the simulated outcomes of the suggested antenna are convenient for UWB-MIMO wireless applications. Measures carried out on the fabricated prototype of the antenna demonstrate good agreement between both the simulation and measurement results of the optimized two-port MIMO antenna