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18 pages, 9553 KiB

Open AccessArticle

Smart, Fast, and Low Memory Beam-Steering Antenna Configurations for 5G and Future Wireless Systems

by Kandasamy Pirapaharan, Nagananthakumaran Ajithkumar, Konesamoorthy Sarujan, Xavier Fernando and Paul R. P. Hoole

Electronics 2022, 11(17), 2658; https://doi.org/10.3390/electronics11172658 - 25 Aug 2022

Cited by 6 | Viewed by 2899

Abstract

Smart Antennas are important to provide mobility support for many enhanced 5G and future wireless applications and services, such as energy harvesting, virtual reality, Voice over 5G (Vo5G), connected vehicles, Machine-to-Machine Communication (M2M), and Internet of Things (IoT). Smart antenna technology enables us [...] Read more.

Smart Antennas are important to provide mobility support for many enhanced 5G and future wireless applications and services, such as energy harvesting, virtual reality, Voice over 5G (Vo5G), connected vehicles, Machine-to-Machine Communication (M2M), and Internet of Things (IoT). Smart antenna technology enables us to reduce interference and multipath problems and increase the quality in communication signals. This paper presents a number of nonlinear configurations of dipole arrays for forming a single beam in any desired direction. We propose three, four, six, and eight-element array structures to perform this single beam-steering functionality. The proposed array configurations with multiple axes of symmetry (in the azimuthal plane) decrease the computational repetitions in optimizing respective weight factors for beam-steering. The optimized weight factors are obtained through the Least Mean Square (LMS) method. MATLAB^TM is used to calculate optimized weight factors as well as to determine the resulting radiation patterns. Since antennas are bidirectional elements, beamforming in one direction means that the antenna will also have high receiving gain in that direction. Performances of differently configured models are compared in terms of their directivity, sidelobe reduction, and computational complexities for beam-steering. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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16 pages, 5264 KiB

Open AccessFeature PaperArticle

Simulating the Dispersion of the Energy Flux Density of the Electromagnetic Field Generated by Antennas for Mobile Communications

by Raimondas Buckus, Aleksandras Chlebnikovas, Birute Strukcinskiene, Rimantas Stukas, Donatas Austys, Jacek Caban, Marcin Bogucki, Aurelija Sidlauskiene, Vaiva Seleviciene, Artūras Kilikevičius, Jonas Matijošius, Kristina Kilikevičienė and Darius Vainorius

Electronics 2022, 11(15), 2431; https://doi.org/10.3390/electronics11152431 - 4 Aug 2022

Cited by 1 | Viewed by 1803

Abstract

The last two decades have faced a significantly increased number of telecommunication antennas emitting electromagnetic radiation in residential areas. The theoretical simulation of the dispersion of the energy flux density of the electromagnetic field has been performed applying the physical peculiarities of the [...] Read more.

The last two decades have faced a significantly increased number of telecommunication antennas emitting electromagnetic radiation in residential areas. The theoretical simulation of the dispersion of the energy flux density of the electromagnetic field has been performed applying the physical peculiarities of the waves generating electromagnetic radiation. Having evaluated studies on simulation, the visual representation of the spread of electromagnetic radiation has been carried out according to the results obtained applying the AutoCad package. A comparison of the simulated value of the energy flux density radiated from antennas for mobile telecommunications with the measured one has disclosed an overlap of 30%. The simulation of the energy flux density showed that, in the close proximity zone (under a distance of 30 m), antennas radiate values within the range 10–10,000 µW/cm². At a distance larger than 30 m, the values of energy flux density fluctuate from 10 to 0.001 µW/cm². Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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15 pages, 5348 KiB

Open AccessArticle

A Miniaturized FSS-Based Eight-Element MIMO Antenna Array for Off/On-Body WBAN Telemetry Applications

by Muhammad Bilal, Sara Shahid, Yousuf Khan, Zahid Rauf, Raja A. Wagan, Muhammad A. Butt, Svetlana N. Khonina and Nikolay L. Kazanskiy

Electronics 2022, 11(4), 522; https://doi.org/10.3390/electronics11040522 - 10 Feb 2022

Cited by 10 | Viewed by 2381

Abstract

In this paper, a compact multiple-input multiple-output (MIMO) antenna for an off/on-body wireless body area network (WBAN) is presented. The proposed antenna comprises eight elements arranged in a side-by-side, orthogonal, and across configuration on a planar laminate. This MIMO system achieves wideband impedance [...] Read more.

In this paper, a compact multiple-input multiple-output (MIMO) antenna for an off/on-body wireless body area network (WBAN) is presented. The proposed antenna comprises eight elements arranged in a side-by-side, orthogonal, and across configuration on a planar laminate. This MIMO system achieves wideband impedance matching, i.e., fractional bandwidth (FBW) = 111% (7600 MHz) when placed off-body and FBW = 110% (7500 MHz) when placed on-body. The achieved bandwidth covers the ultrawideband (UWB) ranges 3.1–10.6 GHz for UWB-WBANs. To isolate the antenna elements, a Jerusalem cross (JC)-shaped frequency-selective surface (FSS) and meandered structure (MS) was designed and optimized. This proposed isolation mechanism offers at least 20 dB of isolation while maintaining an overall compact profile. Moreover, MIMO performance parameters for off/on-body and the specific absorption rate (SAR) were also evaluated. Stable MIMO performance, acceptable limits of SAR, and optimum radiation characteristics verify its suitability for wideband biotelemetry applications. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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20 pages, 4993 KiB

Open AccessArticle

Transparent 2-Element 5G MIMO Antenna for Sub-6 GHz Applications

by Arpan Desai, Merih Palandoken, Issa Elfergani, Ismail Akdag, Chemseddine Zebiri, Joaquim Bastos, Jonathan Rodriguez and Raed A. Abd-Alhameed

Electronics 2022, 11(2), 251; https://doi.org/10.3390/electronics11020251 - 13 Jan 2022

Cited by 33 | Viewed by 2678

Abstract

A dual-port transparent multiple-input multiple-output (MIMO) antenna resonating at sub-6 GHz 5G band is proposed by using patch/ground material as transparent conductive oxide (AgHT-8) and a transparent Plexiglas substrate. Two identical circular-shaped radiating elements fed by using a microstrip feedline are designed using [...] Read more.

A dual-port transparent multiple-input multiple-output (MIMO) antenna resonating at sub-6 GHz 5G band is proposed by using patch/ground material as transparent conductive oxide (AgHT-8) and a transparent Plexiglas substrate. Two identical circular-shaped radiating elements fed by using a microstrip feedline are designed using the finite element method (FEM) based high-frequency structure simulator (HFSS) software. The effect of the isolation mechanism is discussed using two cases. In case 1, the two horizontally positioned elements are oriented in a similar direction with a separate ground plane, whereas in case 2, the elements are vertically placed facing opposite to each other with an allied ground. In both cases, the transparent antennas span over a −10 dB band of 4.65 to 4.97 GHz (300 MHz) with isolation greater than 15 dB among two elements. The diversity parameters are also analyzed for both the cases covering the correlation coefficient (ECC), mean effective gain (MEG), diversity gain (DG), and channel capacity loss (CCL). The average gain and efficiency above 1 dBi and 45%, respectively with satisfactory MIMO diversity performance, makes the transparent MIMO antenna an appropriate choice for smart IoT devices working in the sub-6 GHz 5G band by mitigating the co-site location and visual clutter issues. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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12 pages, 2955 KiB

Open AccessArticle

Fast Hybrid Computational Technique for the Analysis of Radome Structures Using Dual Domain Decomposition

by Carlos Delgado, Eliseo García and Felipe Cátedra

Electronics 2021, 10(18), 2196; https://doi.org/10.3390/electronics10182196 - 8 Sep 2021

Cited by 1 | Viewed by 1549

Abstract

This work details a technique tailored to the analysis of complex radome structures based on the non-overlapping separation of two different domains: antenna and radome. Both domains are analyzed isolated using the method of moments with the multilevel fast multipole algorithm (MoM-MLFMA) for [...] Read more.

This work details a technique tailored to the analysis of complex radome structures based on the non-overlapping separation of two different domains: antenna and radome. Both domains are analyzed isolated using the method of moments with the multilevel fast multipole algorithm (MoM-MLFMA) for the antenna domain and a modified characteristic basis function method with the multilevel fast multipole algorithm approach for the radome domain. An iterative procedure is then applied to compute the effect of each domain over the complementary domain. This approach usually converges into a few iterations, yielding very good results and significant efficiency improvements with respect to other efficient approaches such as a full-wave MoM-MLFMA analysis of the full problem. A realistic test case is included, considering a radome with an embedded frequency selective structure on one of its interfaces. The results show a very good agreement considering only three iterations between domains, requiring only one-third of the CPU-time needed by the conventional approach. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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17 pages, 5786 KiB

Open AccessArticle

Fast Computation by MLFMM-FFT with NURBS in Large Volumetric Dielectric Structures

by Alejandro Pons, Alvaro Somolinos, Ivan González and Felipe Cátedra

Electronics 2021, 10(13), 1560; https://doi.org/10.3390/electronics10131560 - 28 Jun 2021

Cited by 5 | Viewed by 1768

Abstract

A refinement for the computation of the rigorous part of the multi-level fast multipole method (MLFMM) of analyzing volumetric objects is presented. A scheme based on the fast Fourier technique (FFT) is proposed with the objective of reducing the computational resources required to [...] Read more.

A refinement for the computation of the rigorous part of the multi-level fast multipole method (MLFMM) of analyzing volumetric objects is presented. A scheme based on the fast Fourier technique (FFT) is proposed with the objective of reducing the computational resources required to accurately analyze large homogeneous and non-homogeneous dielectric volumes. In order to reduce the memory requirements, the storage of the near-field terms of the method of moments (MoM) matrix is performed only for the positions corresponding to a parallelepiped with the size of the level 1 block of the MLFMM, computed with the vacuum permittivity, taking advantage of the Toeplitz symmetry present in regular hexahedral meshes. The FFT avoids applying the near-field MoM matrix in the iterative solution process. The application of this approach results in huge improvements in terms of memory usage, but also a speeds up the iterative solution process because the use of three-dimensional (3D) FFTs is very efficient for computing convolutions when the number of unknowns of the problems becomes very large as happens in volumetric problems. We also propose a new approach for the numerical treatment of the transition of the dielectric permittivity between different dielectrics or between a dielectric and a free space. To validate the computation technique, the radar cross section (RCS) of several dielectric bodies is computed using the classical MLFMM approach and it is compared with the presented FFT-based-MLFMM solution. The results demonstrate that the efficient memory and computation time usage of the proposed approach. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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14 pages, 2725 KiB

Open AccessCommunication

Comparison between Specialized Quadrature Rules for Method of Moments with NURBS Modelling Applied to Periodic Multilayer Structures

by Rafael Florencio, Álvaro Somolinos, Iván González, Felipe Cátedra and Lorena Lozano

Electronics 2020, 9(12), 2043; https://doi.org/10.3390/electronics9122043 - 2 Dec 2020

Cited by 1 | Viewed by 1482

Abstract

A comparison between Ma-Rokhlin-Wandzura (MRW) and double exponential (DE) quadrature rules for numerical integration of method of moments (MoM) matrix entries with singular behavior is presented for multilayer periodic structures. Non Uniform Rational B-Splines (NURBS) modelling of the layout surfaces is implemented to [...] Read more.

A comparison between Ma-Rokhlin-Wandzura (MRW) and double exponential (DE) quadrature rules for numerical integration of method of moments (MoM) matrix entries with singular behavior is presented for multilayer periodic structures. Non Uniform Rational B-Splines (NURBS) modelling of the layout surfaces is implemented to provide high-order description of the geometry. The comparison is carried out in order to show that quadrature rule is more suitable for MoM matrix computation in terms of sampling, accuracy of computation of MoM matrix, and CPU time consumption. The comparison of CPU time consumption shows that the numerical integration with MRW samples is roughly 15 times faster than that numerical integration using DE samples for results with similar accuracies. These promising results encourage to carry out a comparison with results obtained in previous works where a specialized approach for the specific analysis of split rings geometries was carried out. This previous approach uses spectral MoM version with specific entire domain basis function with edge singularities defined on split ring geometry. Thus, the previous approach provides accurate results with low CPU time consumption to be compared. The comparison shows that CPU time consumption obtained by MRW samples is similar to the CPU time consumption required by the previous work of specific analysis of split rings geometries. The fact that similar CPU time consumptions are obtained by MRW quadrature rules for modelling of general planar geometries and by the specialized approach for split ring geometry provides an assessment for the usage of the MRW quadrature rules and NURBS modelling. This fact provides an efficient tool for analysis of reflectarray elements with general planar layout geometries, which is suitable for reflectarray designs under local periodicity assumption where a huge number of periodic multilayer structures have to be analyzed. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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Review

Jump to: Research

21 pages, 405 KiB

Open AccessReview

Trends of Microwave Devices Design Based on Artificial Neural Networks: A Review

by Andrius Katkevičius, Darius Plonis, Robertas Damaševičius and Rytis Maskeliūnas

Electronics 2022, 11(15), 2360; https://doi.org/10.3390/electronics11152360 - 28 Jul 2022

Cited by 4 | Viewed by 1947

Abstract

The usage of techniques of the artificial neural networks (ANNs) in the field of microwave devices has recently increased. The advantages of ANNs in comparison with traditional full-wave methods are that the prediction speed when the traditional time-consuming iterative calculations are not required [...] Read more.

The usage of techniques of the artificial neural networks (ANNs) in the field of microwave devices has recently increased. The advantages of ANNs in comparison with traditional full-wave methods are that the prediction speed when the traditional time-consuming iterative calculations are not required and also the complex mathematical model of the microwave device is no longer needed. Therefore, the design of microwave device could be repeated many times in real time. However, methods of artificial neural networks still lag behind traditional full-wave methods in terms of accuracy. The prediction accuracy depends on the structure of the selected neural network and also on the obtained dataset for the training of the network. Therefore, the paper presents a systematic review of the implementation of ANNs in the field of the design and analysis of microwave devices. The guidelines for the systematic literature review and the systematic mapping research procedure, as well as the Preferred Report Items for Systematic Reviews and Meta-Analysis statements (PRISMA) are used to conduct literature search and report the results. The goal of the paper is to summarize the application areas of usage of ANNs in the field of microwave devices, the type and structure of the used artificial neural networks, the type and size of the dataset, the interpolation and the augmentation of the training dataset, the training algorithm and training errors and also to discuss the future perspectives of the usage of ANNs in the field of microwave devices. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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25 pages, 678 KiB

Open AccessReview

FDTD-Based Electromagnetic Modeling of Dielectric Materials with Fractional Dispersive Response

by Luciano Mescia, Pietro Bia and Diego Caratelli

Electronics 2022, 11(10), 1588; https://doi.org/10.3390/electronics11101588 - 16 May 2022

Cited by 6 | Viewed by 2893

Abstract

The use of fractional derivatives and integrals has been steadily increasing thanks to their ability to capture effects and describe several natural phenomena in a better and systematic manner. Considering that the study of fractional calculus theory opens the mind to new branches [...] Read more.

The use of fractional derivatives and integrals has been steadily increasing thanks to their ability to capture effects and describe several natural phenomena in a better and systematic manner. Considering that the study of fractional calculus theory opens the mind to new branches of thought, in this paper, we illustrate that such concepts can be successfully implemented in electromagnetic theory, leading to the generalizations of the Maxwell’s equations. We give a brief review of the fractional vector calculus including the generalization of fractional gradient, divergence, curl, and Laplacian operators, as well as the Green, Stokes, Gauss, and Helmholtz theorems. Then, we review the physical and mathematical aspects of dielectric relaxation processes exhibiting non-exponential decay in time, focusing the attention on the time-harmonic relative permittivity function based on a general fractional polynomial series approximation. The different topics pertaining to the incorporation of the power-law dielectric response in the FDTD algorithm are explained, too. In particular, we discuss in detail a home-made fractional calculus-based FDTD scheme, also considering key issues concerning the bounding of the computational domain and the numerical stability. Finally, some examples involving different dispersive dielectrics are presented with the aim to demonstrate the usefulness and reliability of the developed FDTD scheme. Full article

(This article belongs to the Special Issue Numerical Electromagnetic Problems Involving Antennas)

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