Sector Unit-Cell Methodology for the Design of Sub-6 GHz 5G MIMO Antennas

[EN] A novel methodology based on the sectorization of multiple-port cavities with azimuthal symmetry into sector unit cells is presented to design 5G multiple-input multiple-output (MIMO) sub-6 GHz antennas. The methodology divides an N-port cavity antenna into N unit cells and predicts the performance of the N-port design with the analysis of two adjacent cells. This approximation reduces the time and complexity of the simulation of cavity antennas with a high number of ports. For the theoretical justification, cavity mode analysis of a closed cavity and characteristic modes analysis of open and sector cavities is addressed. With the use of the proposed methodology, five different cavity designs with circular, square, hexagonal, octagonal, and saw-tooth geometries are presented in this article. In addition, the fabrication of the 4-port circular shape design and its MIMO performance is also studied. Results show an impedance bandwidth of 130% (1.27-6 GHz), and an envelope correlation coefficient (ECC) lower than 0.1.This work was supported by the Spanish Ministry of Science and Innovation (Ministerio Ciencia e Innovacion) under Project PID2019-107885GB-C32.Molins-Benlliure, J.; Cabedo Fabres, M.; Antonino Daviu, E.; Ferrando Bataller, M. (2022). Sector Unit-Cell Methodology for the Design of Sub-6 GHz 5G MIMO Antennas. IEEE Access. 10:100824-100836. https://doi.org/10.1109/ACCESS.2022.32071631008241008361

UWB Reflectarray Antenna for Chipless RFID Reader Gain Enhancement

The main limitation of chipless Radio Frequency Identification (RFID) systems is its short reading range which is generally less than  as the amplitude of the back scattered tag signal is inversely proportional to the fourth root of the reading distance. In this paper, a design of reflectarray (RA) antenna consisting of unified unit cell. Five different unit cells structures centered at 6GHz for chipless RFID reader applications is introduced. The proposed RA has a narrow half power beam width (HPBW) and high gain which significantly enhance the reader sensitivity, maximize the reader reading range, reduce the multipath effects, and improve the tag localization. The proposed RA is realized on a rectangular single layer Rogers RT5880 lossy substrate of thickness and relative permittivity. radiating cells or elements with uniform element spacing are arranged on the rectangular substrate of dimensions and fed by a pyramidal horn antenna with gain of   and HPBW equals 46.7°and 42.8° at E-plane and H-plane respectively. The simulation results showed that the proposed RA gives high gain up to which is greater than the feeder gain by and three times narrower HPBW of about .It operates over frequency range from to with fractional bandwidth (FBW) and has side lobe level,, which can't be achieved by the conventional antenna arrays

Cross-Entropy Method for Design and Optimization of Pixelated Metasurfaces

© 2013 IEEE. Electromagnetic metasurfaces are planar two-dimensional metamaterials, typically of subwavelength thickness. Unit cell elements of different shapes have been widely explored, including electric and magnetic dipoles, patches, arbitrary geometries and pixelated surfaces. Although pixelated metasurfaces have a great advantage of geometric versatility, their design and analysis requires algorithmic approach. One of the techniques for their design is via evolutionary simulation-driven optimization. Since full-wave electromagnetic simulations are time-consuming, optimization methods with fast convergence properties are preferable. In this article, we demonstrate the application of the cross-entropy optimization method to design of artificial magnetic conductors (AMCs) and thin printed phase shifters. Single-frequency AMCs at 10 GHz (X band) and dual-frequency AMCs at 8 and 12 GHz (X and Ku band) were produced that are more manufacturing-friendly, and thus cost effective, than previously reported AMCs. We also show that phase-shifting unit cells with transmission magnitudes over 0.9 (linear) can be designed using the proposed optimization technique. Other potential applications of these unit cells are in phase-correcting and beam-steering metasurfaces

Antenna Designs for 5G/IoT and Space Applications

This book is intended to shed some light on recent advances in antenna design for these new emerging applications and identify further research areas in this exciting field of communications technologies. Considering the specificity of the operational environment, e.g., huge distance, moving support (satellite), huge temperature drift, small dimension with respect to the distance, etc, antennas, are the fundamental device allowing to maintain a constant interoperability between ground station and satellite, or different satellites. High gain, stable (in temperature, and time) performances, long lifecycle are some of the requirements that necessitates special attention with respect to standard designs. The chapters of this book discuss various aspects of the above-mentioned list presenting the view of the authors. Some of the contributors are working strictly in the field (space), so they have a very targeted view on the subjects, while others with a more academic background, proposes futuristic solutions. We hope that interested reader, will find a fertile source of information, that combined with their interest/background will allow efficiently exploiting the combination of these two perspectives

A Wideband and Polarization-Independent Metasurface Based on Phase Optimization for Monostatic and Bistatic Radar Cross Section Reduction

A broadband and polarization-independent metasurface is analyzed and designed for both monostatic and bistatic radar cross section (RCS) reduction in this paper. Metasurfaces are composed of two types of electromagnetic band-gap (EBG) lattice, which is a subarray with “0” or “” phase responses, arranged in periodic and aperiodic fashions. A new mechanism is proposed for manipulating electromagnetic (EM) scattering and realizing the best reduction of monostatic and bistatic RCS by redirecting EM energy to more directions through controlling the wavefront of EMwave reflected from the metasurface. Scattering characteristics of two kinds of metasurfaces, periodic arrangement and optimized phase layout, are studied in detail. Optimizing phase layout through particle swarm optimization (PSO) together with far field pattern prediction can produce a lot of scattering lobes, leading to a great reduction of bistatic RCS. For the designed metasurface based on optimal phase layout, a bandwidth of more than 80% is achieved at the normal incidence for the −9.5 dB RCS reduction for both monostatic and bistatic. Bistatic RCS reduction at frequency points with exactly 180∘ phase difference reaches 17.6 dB. Both TE and TM polarizations for oblique incidence are considered. The measured results are in good agreement with the corresponding simulations

Passive Planar Microwave Devices

The aim of this book is to highlight some recent advances in microwave planar devices. The development of planar technologies still generates great interest because of their many applications in fields as diverse as wireless communications, medical instrumentation, remote sensing, etc. In this book, particular interest has been focused on an electronically controllable phase shifter, wireless sensing, a multiband textile antenna, a MIMO antenna in microstrip technology, a miniaturized spoof plasmonic antipodal Vivaldi antenna, a dual-band balanced bandpass filter, glide-symmetric structures, a transparent multiband antenna for vehicle communications, a multilayer bandpass filter with high selectivity, microwave planar cutoff probes, and a wideband transition from microstrip to ridge empty substrate integrated waveguide

A review of manufacturing materials and production methods for frequency-selective structures [wireless corner]

This article presents a review of frequency-selective structure (FSS) manufacturing materials and production methods ranging from the common printed circuit board (PCB)-based designs to textile, ink, metal, or fluid prototypes. Our work gathers some of the most relevant solutions published by the scientific community and considers several examples depicted for each case. Additionally, the main physical parameters that may have a significant impact on FSS performance have been identified, e.g., electrical conductivity of the FSS conductive element and the relative permittivity and thickness of the FSS dielectric material. Finally, a comparative analysis of the materials and techniques is presented, which highlights the benefits and limitations of each solution.Fundação para a Ciência e a Tecnologia | Ref. POCI-01- 0247-FEDER- 017867Ministerio de Economía y Competitividad | Ref. TEC2014-55735-C03-

Positioning of a wireless relay node for useful cooperative communication

Given the exorbitant amount of data transmitted and the increasing demand for data connectivity in the 21st century, it has become imperative to search for pro-active and sustainable solutions to the effectively alleviate the overwhelming burden imposed on wireless networks. In this study a Decode and Forward cooperative relay channel is analyzed, with the employment of Maximal Ratio Combining at the destination node as the method of offering diversity combining. The system framework used is based on a three-node relay channel with a source node, relay node and a destination node. A model for the wireless communications channel is formulated in order for simulation to be carried out to investigate the impact on performance of relaying on a node placed at the edge of cell. Firstly, an AWGN channel is used before the effect of Rayleigh fading is taken into consideration. Result shows that performance of cooperative relaying performance is always superior or similar to conventional relaying. Additionally, relaying is beneficial when the relay is placed closer to the receiver