Antenna Design for 5G and Beyond

With the rapid evolution of the wireless communications, fifth-generation (5G) communication has received much attention from both academia and industry, with many reported efforts and research outputs and significant improvements in different aspects, such as data rate speed and resolution, mobility, latency, etc. In some countries, the commercialization of 5G communication has already started as well as initial research of beyond technologies such as 6G.MIMO technology with multiple antennas is a promising technology to obtain the requirements of 5G/6G communications. It can significantly enhance the system capacity and resist multipath fading, and has become a hot spot in the field of wireless communications. This technology is a key component and probably the most established to truly reach the promised transfer data rates of future communication systems. In MIMO systems, multiple antennas are deployed at both the transmitter and receiver sides. The greater number of antennas can make the system more resistant to intentional jamming and interference. Massive MIMO with an especially high number of antennas can reduce energy consumption by targeting signals to individual users utilizing beamforming.Apart from sub-6 GHz frequency bands, 5G/6G devices are also expected to cover millimeter-wave (mmWave) and terahertz (THz) spectra. However, moving to higher bands will bring new challenges and will certainly require careful consideration of the antenna design for smart devices. Compact antennas arranged as conformal, planar, and linear arrays can be employed at different portions of base stations and user equipment to form phased arrays with high gain and directional radiation beams. The objective of this Special Issue is to cover all aspects of antenna designs used in existing or future wireless communication systems. The aim is to highlight recent advances, current trends, and possible future developments of 5G/6G antennas

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

Modelling of mmWave Propagation Channel for Off-body Communication Scenarios

Předkládaná disertační práce je zaměřena na \uv{Modelování propagačního kanálu pro off-body komunikaci v oblasti milimetrových vln}. Navzdory pokrokům v rámci bezdrátových sítí v přímé blízkosti člověka stále systémy 5. generace postrádají dostatečnou šířku pásma a dostatečně nízkou odezvu. To je způsobeno neefektivním využíváním rádiového spektra. Tento nedostatek je potřeba co nejdříve odstranit a právě z tohoto důvodu je hlavním cílem této práce navrhnout vylepšený model rádiového kanálů pro off-body komunikaci. Úkolem tohoto modelu je umožnit uživatelům efektivněji a přesněji simulovat propagaci signálu v rámci daného prostředí. Navržený model je dále optimalizován a ověřen vůči nejnovějším měřením, získaným z literatury. Nakonec je tento model implementován do simulačního nástroje NS-3, pomocí kterého je následně využit k simulaci množství scénářů. Hlavním výstupem této práce je ověřený model přenosového kanálu pro off-body komunikaci v rámci milimetrových vln, společně s jeho implementací do simulačního nástroje NS-3, díky čemuž je dostupný pro širokou veřejnost.This thesis addresses the \uv{Modeling of mmWave Propagation Channel for Off-body Communication Scenarios}. Despite the advancements in the body area wireless networks, the 5G systems are still struggling with not enough bandwidth and large latency due to inefficient utilization of radio spectrum. This issue calls for immediate action and therefore the main aim of this Ph.D. thesis is to propose a novel mmWave off-body channel, which will enable its users to more effectively simulate the signal propagation. The proposed model is further optimized and verified against state-of-the-art measurements from the literature. Finally, the developed model is implemented into the NS-3 simulator and utilized for plethora of simulation scenarios. The main output of this thesis is the verified developed model as well as the implementation inside the NS-3 simulator, which enables a wide society to use it.

Antenna Design for 5G and Beyond

This book is a reprint of the Special Issue Antenna Design for 5G and Beyond that was published in Sensors

Evaluation of mmWave 5G Performance by Advanced Ray Tracing Techniques

Technological progress leads to the emergence of new concepts, which can change people’s everyday lives and accelerate the transformation of many industries. Among the more recent of these revolutionary concepts are big data analysis, artificial intelligence, augmented/virtual reality, quantum computing, and autonomous vehicles. However, this list would be incomplete without referring to fifth-generation (5G) technology, which is driven by several trends. First, the exponential growth of the worldwide monthly smartphone traffic up to 50 petabytes during the next three years will require the development of mobile networks supporting high datasharing capabilities, excellent spectral efficiency, and gigabits per second of throughput. Another trend is Industry 4.0/5.0 (also called the smart factory), which refers to advanced levels of automation requiring millions of distributed sensors/devices connected into a scalable and smart network. Finally, the automation of critical industrial processes, as well as communication between autonomous vehicles, will require 99.999% reliability and under 1 ms latency as they also become the drivers for the emergence of 5G. Besides traditional sub-6 GHz microwave spectrum, the 5G communication encompasses the novel millimeter-wave bands to mitigate spectrum scarcity and provide large bandwidth of up to several GHz. However, there are challenges to be overcome with the millimeter-wave band. The band suffers from higher pathloss, more atmospheric attenuation, and higher diffraction losses than microwave signals. Because the millimeter-wave band has such a small wavelength (< 1 cm), it is now feasible to implement compact antenna arrays. This enables the use of beamforming and multi-input and multi-output techniques. In this thesis, advanced ray tracing methodology is developed and utilized to simulate the propagation mechanisms and their effect on the system-level metrics. The main novelty of this work is in the introduction of typical millimeter-wave 5G technologies into channel modelling and propagation specifics into the system-level simulation, as well as the adaptation of the ray tracing methods to support extensive simulations with multiple antennas

Application of Ultra-Wideband Technology to RFID and Wireless Sensors

Aquesta Tesi Doctoral estudia l'ús de tecnologia de ràdio banda ultraampla (UWB) per sistemes de identificació per radiofreqüència (RFID) i sensors sense fils. Les xarxes de sensors sense fils (WSNs), ciutats i llars intel•ligents, i, en general, l'Internet de les coses (IoT) requereixen interfícies de ràdio simples i de baix consum i cost per un número molt ampli de sensors disseminats. UWB en el domini temporal es proposa aquí com una tecnologia de radio habilitant per aquestes aplicacions. Un model circuital s'estudia per RFID d'UWB codificat en el temps. Es proposen lectors basats en ràdars polsats comercials amb tècniques de processat de senyal. Tags RFID sense xip (chipless) codificats en el temps son dissenyats i caracterizats en termes de número d'identificacions possible, distància màxima de lectura, polarització, influència de materials adherits, comportament angular i corbatura del tag. Es proposen sensors chipless de temperatura i composició de ciment (mitjançant detecció de permitivitat). Dos plataformes semipassives codificades en temps (amb un enllaç paral•lel de banda estreta per despertar el sensor i estalviar energia) es proposen com solucions més complexes i robustes, amb una distància de lectura major. Es dissenya un sensor de temperatura (alimentat per energia solar) i un sensor de diòxid de nitrogen (mitjançant nanotubs de carboni i alimentat per una petita bateria), ambdòs semipassius amb circuiteria analògica. Es dissenya un multi-sensor semipassiu capaç de mesurar temperatura, humitat, pressió i acceleració, fent servir un microcontrolador de baix consum digital. Combinant els tags RFID UWB codificats en temps amb tecnologia de ràdar de penetració del terra (GPR), es deriva una aplicació per localització en interiors amb terra intel•ligent. Finalment, dos sistemes actius RFID UWB codificats en el temps s'estudien per aplicacions de localització de molt llarg abast.Esta Tesis Doctoral estudia el uso de tecnología de radio de banda ultraancha (UWB) para sistemas de identificación por radiofrecuencia (RFID) y sensores inalámbricos. Las redes de sensores inalámbricas (WSNs), ciudades y casas inteligentes, y, en general, el Internet de las cosas (IoT) requieren de interfaces de radio simples y de bajo consumo y coste para un número muy amplio de sensores diseminados. UWB en el dominio temporal se propone aquí como una tecnología de radio habilitante para dichas aplicaciones. Un modelo circuital se estudia para RFID de UWB codificado en tiempo. Configuraciones de lector, basadas en rádar pulsados comerciales, son propuestas, además de técnicas de procesado de señal. Tags RFID sin chip (chipless) codificados en tiempo son diseñados y caracterizados en términos de número de identificaciones posible, distancia máxima de lectura, polarización, influencia de materiales adheridos, comportamiento angular y curvatura del tag. Se proponen sensores chipless de temperatura y composición de cemento (mediante detección de permitividad). Dos plataformas semipasivas codificadas en tiempo (con un enlace paralelo de banda estrecha para despertar el sensor y ahorrar energía) se proponen como soluciones más complejas y robustas, con una distancia de lectura mayor. Se diseña un sensor de temperatura (alimentado por energía solar) y un sensor de dióxido de nitrógeno (mediante nanotubos de carbono y alimentado por una batería pequeña), ambos semipasivos con circuitería analógica. Se diseña un multi-sensor semipasivo capaz de medir temperatura, humedad, presión y aceleración, usando un microcontrolador digital de bajo consumo. Combinando los tags RFID UWB codificados en tiempo y tecnología de radar de penetración de suelo (GPR), se deriva una aplicación para localización en interiores con suelo inteligente. Finalmente, dos sistemas activos RFID UWB codificados en tiempo se estudian para aplicaciones de localización de muy largo alcance.This Doctoral Thesis studies the use of ultra-wideband (UWB) radio technology for radio-frequency identification (RFID) and wireless sensors. Wireless sensor networks (WSNs) for smart cities, smart homes and, in general, Internet of Things (IoT) applications require low-power, low-cost and simple radio interfaces for an expected very large number of scattered sensors. UWB in time domain is proposed here as an enabling radio technology. A circuit model is studied for time-coded UWB RFID. Reader setups based on commercial impulse radars are proposed, in addition to signal processing techniques. Chipless time-coded RFID tags are designed and characterized in terms of number of possible IDs, maximum reading distance, polarization, influence of attached materials, angular behaviour and bending. Chipless wireless temperature sensors and chipless concrete composition sensors (enabled by permittivity sensing) are proposed. Two semi-passive time-coded RFID sensing platforms are proposed as more complex, more robust, and longer read-range solutions. A wake-up link is used to save energy when the sensor is not being read. A semi-passive wireless temperature sensor (powered by solar energy) and a wireless nitrogen dioxide sensor (enabled with carbon nanotubes and powered by a small battery) are developed, using analog circuitry. A semi-passive multi-sensor tag capable of measuring temperature, humidity, pressure and acceleration is proposed, using a digital low-power microcontroller. Combining time-coded UWB RFID tags and ground penetrating radar, a smart floor application for indoor localization is derived. Finally, as another approach, two active time-coded RFID systems are developed for very long-range applications

Characterization and Modelling of Scattered Wireless Channel at 60 GHZ in an Underground Mine Gallery

RÉSUMÉ Depuis plus d’une décennie, les applications du système de communication sans fil sont exigeantes et augmentent rapidement pour fournir des services multimédias au public. De nos jours, la recherche se concentre sur la conception de communication sans fil à haute vitesse (i.e., 1 Gbps) en particulier dans des zones denses telles que des salles de conférence, des centres commerciaux,des stades et des lieux d’événements publics ouverts. Des réseaux locaux sans fil (WLAN) et des réseaux cellulaires utilisent des hauts potentiels pour réussir les haut débit de données en utilisant différentes technologies de pointe telles que la coexistence entre l’évaluation à long terme non autorisé (LTE-U) et les canaux Wi-Fi. En outre, la faisabilité d’utiliser le spectre à haute fréquence (i.e,> 6 GHz), une couche physique à 60 GHz pour les réseaux denses sont mis en évidence lorsque des liens de communication à courte distance (par exemple, <10 m) sont nécessaires aussi bien dans WLAN (i.e, WiGig) et le réseau cellulaire (i.e, 5G petite cellule). Cependant, les applications à 60 GHz se dirigent vers la communication sans fil souterraine pour une meilleure géolocalisation, les applications haute définition (HD) de streaming vidéo dans une galerie plus grande longueur (i.e,> 100 m) en raison de sa capacité de formation de faisceau et de plus grande capacité. Pour aider le concepteur du système, il est nécessaire de connaître les informations de propagation du canal sans fil diffusé puisque le plancher de la galerie, le plafond et le mur ont différentes rugosités (i.e.,> 5 mm). Cette thèse présente les résultats de la caractérisation du canal sans fil et la modélisation statistique à 60 GHz d’une mine souterraine à CANMET ayant des galeries dont la profondeur varie entre 40 m et 70 m. Depuis plus d’une décennie, les applications du système de communication sans fil sont exigeantes et augmentent rapidement pour fournir des services multimédias au public. Les résultats montrent que l’écart angulaire de la propagation par trajets multiples est inversement proportionnel à la distance entre l’émetteur et le récepteur. Un phénomène de dispersion solide est également observé dans le canal en observant l’angle de propagation des différents trajets. Des polarisations horizontales (H) et verticales (V) ont été utilisées puisque les diagrammes de rayonnement sont différents et peuvent fournir des comportements de dispersion temporelle différents. Les résultats montrent que l’antenne à polarisation verticale fournit un plus grand nombre de trajets multiples par rapport à polarisation horizontale et une valeur plus élevée de moyenne quadratique (RMS) par rapport à une horizontale. Par ailleurs, les mesures du coefficient de réflexion ont été effectuées pour étudier l’effet de dispersion de la surface rugueuse. Étant donné qu’aucun effet de regroupement sur le canal multitrajets n’a été observé, une approche de modélisation statistique a été considérée en tenant compte des différents trajets parcourus et leur amplitude. Par insertion des paramètres de hauteur de la surface de mesure, les modèles de diffusion connus ont également été analysées pour permettre la mise en oeuvre d’une approche de modélisation du canal dispersif.----------ABSTRACT More than a decade, there is a surge in demand and development of wireless communication system applications to deliver multimedia services. Nowadays the research is focused on the design of high speed (i.e., 1 Gbps) wireless system particularly in dense areas such as conference room, shopping mall, stadium and open public events. Wireless local area network (WLAN) and cellular network are making high potential approaches to fulfill high data rate by using different advanced technologies such as coexistence between Long Term Evaluation Unlicensed (LTE-U) and Wi-Fi Wireless channels. Moreover, the feasibility to use high-frequency spectrum (i.e., > 6 GHz), a physical layer research at 60 GHz for dense networks are highlighted where short-distance communication links (i.e., 100 m) due to its beamforming capability and higher capacity. To assist the system designer, it is necessary to know the scattered wireless channel propagation information since the gallery floor, ceiling and walls consist of the different magnitude of the roughness (i.e., > 5 mm). This thesis presents the results of wireless channel characterization and statistical modeling at 60 GHz where the measurements were carried out in CANMET underground mine (40 m and 70 m gallery depths). Several measurements were conducted with different antenna configurations and polarizations. Results show that angular and temporal dispersion are proportional to the mine gallery dimensions. Results also show that the angular spread of the multipath is inversely proportional to the transmitter receiver separation distance. A strong scattering phenomenon is also observed in the channel by observing multipath angle of arrivals. The use of Horizontal (H) and vertical (V) polarizations were performed due to its different radiation pattern can provide a different temporal dispersion behavior. The results show that a vertically polarized antenna provides a lower value of path loss exponent and a higher value of root mean square (RMS) delay spread compared to a horizontal one. Since no clustering effect was observed, a statistical modeling approach with the multipath arrivals and amplitudes was considered. In addition, the reflection coefficient measurements were conducted to investigate the scattering effect from the rough surface. By inserting measured surface height parameters, the known scattering models were also analyzed to have an idea to implement a modeling approach of the scattered channel