Optimum polarization configuration of planar circular patch MIMO antenna

Multiple Input Multiple Output (MIMO) is a key technology that plays an important role in achieving the 5G requirement due to its capability to increase channel capacity. However, the increase of channel capacity is influenced by several aspects such as mutual coupling. Many methods are done to decrease the mutual coupling effect such as polarization arrangement of the MIMO antennas. This study on the polarization arrangement of a circular patch MIMO antenna at 3.5 GHz was performed. Four elements of the MIMO antenna are arranged with several polarization configurations both in Co-Polarization and Cross-Polarization. Both simulation and measurement results showed that MIMO with Co-Polarization has a slightly wider bandwidth equal to 295.25 MHz compared to Cross-Polarization with a bandwidth of 274.63 MHz, due to better return loss performed by the former. However, from the mutual coupling perspective, it is observed that MIMO with Cross-Polarization can reduce the mutual coupling from -17.6676dB into -22.462 dB compared to Co-Polarization with the same element distance.Multiple Input Multiple Output (MIMO) merupakan teknologi kunci yang memiliki peran penting dalam pencapaian kebutuhan jaringan 5G karena kemampuannya untuk meningkatkan kapasitas kanal. Tetapi, peningkatan kapasitas kanal dipengaruhi oleh beberapa aspek yaitu salah satunya mutual coupling. Beberapa metode yang dilakukan untuk mengurangi efek mutual coupling antara lain susunan polarisasi dari antena MIMO. Penelitian kali ini berfokus kepada susunan polarisasi dari antenna MIMO berbentuk circular patch  dengan frekuensi 3.5 GHz. Empat elemen MIMO disusun dengan beberapa konfigurasi polarisasi yaitu Co-Polarization dan Cross-Polarization. Hasil simulasi dan pengukuran menunjukan bahwa MIMO dengan Co-Polarization memiliki pita yang lebih lebar sebesar 295.25 MHz dibandingkan dengan Cross-Polarization dengan lebar pita hanya 274.63 MHz, karena return loss yang lebih baik pada Co-Polarization. Akan tetapi, dari perspektif mutual couping, dapat diamati bahwa MIMO dengan Cross-Polarization dapat mengurangi mutual coupling dari -17.667 dB ke -22.462 dB dibandingkan dengan Co-Polarization dengan jarak elemen yang sam

Orbital Angular Momentum Waves: Generation, Detection and Emerging Applications

Orbital angular momentum (OAM) has aroused a widespread interest in many fields, especially in telecommunications due to its potential for unleashing new capacity in the severely congested spectrum of commercial communication systems. Beams carrying OAM have a helical phase front and a field strength with a singularity along the axial center, which can be used for information transmission, imaging and particle manipulation. The number of orthogonal OAM modes in a single beam is theoretically infinite and each mode is an element of a complete orthogonal basis that can be employed for multiplexing different signals, thus greatly improving the spectrum efficiency. In this paper, we comprehensively summarize and compare the methods for generation and detection of optical OAM, radio OAM and acoustic OAM. Then, we represent the applications and technical challenges of OAM in communications, including free-space optical communications, optical fiber communications, radio communications and acoustic communications. To complete our survey, we also discuss the state of art of particle manipulation and target imaging with OAM beams

Dual-band circularly polarized MIMO DRA for sub-6 GHz applications

In this article, a dual-band circularly polarized multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is proposed for 3.5 and 5.5 GHz bands, both being located under 6 GHz. Known as sub-6 (or as mid-band), they provide good coverage and capacity in the newly targeted fifth-generation (5G) systems. The proposed structure consists of two ring DRAs (RDRAs) etched on a 0.8 mm thick RT Duroid substrate. Measured impedance bandwidths in broadside direction are 3.1-3.75 GHz (19%) and 5.3-5.6 GHz (9.4%) and circular polarization (CP) bandwidths are 3.425-3.6 GHz (5%) and 5.45-5.55 GHz (2%), respectively. CP is achieved by exciting HE modes using two probes placed orthogonaly to each other, that is, at an azimuthal angular distance of 90∘. Varying the lengths of the probe allows achieving the necessary time-phase quadrature between modes. Comparison between recent multiband circularly polarized MIMO DRAs and proposed prototype has revealed that CP bandwidth in both bands is one of the highlighting advantages of the present configuration

Agregados de antenas para sistemas massive MIMO 5G e satélite

Wireless telecommunications systems are growing and improving at a breakneck pace, and its demands must be ful lled with hardware modi cations. The fth-generation will demand a revolution since antennas are going to be designed for high frequency, millimeter wave bands, where there is a lot of unexploited spectrum worldwide. However, these frequencies get absorbed quite easily, for example, they su er high attenuation due to rain. This implies a decrease of radiated power. To solve some of the issues, antenna arrays have been studied due to their high versatility. This dissertation has the goal of designing and testing several solutions based on microstrip patch antennas. Initially, an analysis of the coupling between elements is performed as well as some proposed techniques to reduce it, through more compact spaces, without any gain decreasing. Finally, considering the space limitations, series antenna arrays are developed for satellite communications and presented an indepth study of antennas effciently employed for both transmission and reception simultaneously.Os sistemas de telecomunicações sem fios continuam a crescer e a melhorar a um ritmo frenetico, por isso, novos requisitos tem de ser cumpridos com modificações ao nível do hardware. A quinta geração exigirá uma revolução, uma vez que as antenas serão projetadas para alta frequência, banda de ondas milimétricas, onde o espetro ainda não foi muito explorado. No entanto, estas frequências são absorvidas com facilidade como, por exemplo, na atmosfera devido á atenuação originada pela chuva. Para resolver estas limitações, os agregados de antenas têm sido estudados devido á sua versatilidade. Esta dissertação tem o objetivo de desenhar e testar várias soluções baseadas em antenas microstrip (patch). Inicialmente, é realizada uma avaliação do acoplamento entre elementos e propostas algumas técnicas de redução do mesmo, utilizando espaços mais compactos que o usual, mas prevenindo quaisquer diminuições de ganho. Por fim, tendo em vista a mesma limitação espacial, são desenvolvidos agregados de antenas em série direcionados para comunicações via satélite e apresentado um estudo detalhado de antenas para transmissão e recepção em simultâneo.Mestrado em Engenharia Eletrónica e Telecomunicaçõe

A Novel Single-Fed Dual-Band Dual-Circularly Polarized Dielectric Resonator Antenna for 5G Sub-6GHz Applications

In this research article, a single-fed dual-band circular polarized (CP) dielectric resonator antenna (DRA) for dual-function communication, such as GPS and WLAN, was made. Initially, the proposed design process was initiated by designing a linearly polarized singly fed-DRA. To attain CP fields, the cross-shape conformal metal strip was optimized to excite the fundamental and the high-order mode in the two frequency bands. The metallic strip (parasitic) was utilized on top of the rectangular DRA to improve and widen the impedance and axial ratio (AR) bandwidth. This step led to a 2.73% improvement on the lower band and an impact of 6.5% on the upper band while on the other side a significant improvement was witnessed in the AR bandwidth in both frequency bands. A prototype was designed and fabricated in order to validate its operations. The measurement outcomes of the proposed antennas authenticated wideband impedance bandwidths of 6.4% and 25.26%, and 3-dB axial ratios (AR) of 21.26% and 27.82% respectively. The prototype is a decent candidate for a global positioning system (GPS) and wireless local area network (WLAN).This project has received funding from the Universidad Carlos III de Madrid and the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska- Curie Grant 801538

Novel Pseudo Magneto-electric Dipole Antennas

One of the major requirements for modern wireless communications is very high data transmission, so antennas with simple geometry, wide operation bandwidth and stable high gain features are in increasing demand. In this thesis, three novel pseudo magneto-electric (ME) dipole antennas operating in 5G Frequency Range 1 (FR1) sub-6GHz and Frequency Range 2 (FR2) millimeter-wave (mmW) band are introduced and analyzed. Comparing with conventional ME dipole antennas, which always require a vertical quarter-wave cavity to generate the magnetic dipole resonance, the pseudo-ME dipole designs proposed in this thesis do not rely on the cavity to provide the complementary magnetic dipole mode, therefore, they have extremely simple geometry. Meanwhile, it achieved wide bandwidth (50.30%) and high gain (average 8.74 dBi) the in-band gain variation is only ± 1dB. Based on the novel cavity-less Pseudo-ME dipole antenna geometry, a wide axial ratio bandwidth (54.1%) circularly polarized pseudo-ME dipole antenna is also designed to overcome the polarization misalignment problem in multipath-rich wireless environments, this antenna has two pairs of orthogonal electric dipoles and magnetic dipoles to achieve the wide axial ratio bandwidth performance. Finally, an aperture-coupled printed pseudo-ME dipole antenna is designed for operating in millimeter-wave band, it has 32.3% of impedance bandwidth and stable high gain 7.4 ± 0.8 dBi. Especially, there is none typical via-hole formed cavity in the geometry, so the fabrication of the mmW band antenna becomes simpler

Millimeter-Wave Components and Antennas for Spatial and Polarization Diversity using PRGW Technology

The evolution of the wireless communication systems to the future generation is accompanied by a huge improvement in the system performance through providing a high data rate with low latency. These systems require access to millimeter wave (mmWave) bands, which offer several advantages such as physically smaller components and much wider bandwidthcomparedtomicrowavefrequencies. However, mmWavecomponentsstillneed a significant improvement to follow the rapid variations in future technologies. Although mmWave frequencies can carry more data, they are limited in terms of their penetration capabilities and their coverage range. Moreover, these frequencies avoid deploying traditional guiding technologies such as microstrip lines due to high radiation and material losses. Hence, utilizing new guiding structure techniques such as Printed Ridge Gap Waveguide (PRGW) is essential in future mmWave systems implementation. ThemainpurposeofthisthesisistodesignmmWavecomponents,antennasubsystems and utilize both in beam switching systems. The major mmWave components addressed in this thesis are hybrid coupler, crossover, and differential power divider where the host guidingstructureisthePRGW.Inaddition,variousdesignsfordifferentialfeedingPRGW antennas and antenna arrays are presented featuring wide bandwidth and high gain in mmWave band. Moreover, the integration of both the proposed components and the featured antennas is introduced. This can be considered as a significant step toward the requirements fulfillment of today's advanced communication systems enabling both space and polarization diversity. The proposed components are designed to meet the future ever-increasing consumer experience and technical requirements such as low loss, compact size, and low-cost fabrication. This directed the presented research to have a contribution into three major parts. The first part highlights the feeding structures, where mmWave PRGW directional couplers and differential feeding power divider are designed and validated. These components are among the most important passive elements of microwave circuits used in antennabeam-switchingnetworks. Different3-dBquadraturehybridcouplersandcrossover prototypes are proposed, featured with a compact size and a wide bandwidth beyond 10 % at 30 GHz. In the second part, a beam switching network implemented using hybrid couplers is presented. The proposed beam switching network is a 4 × 4 PRGW Butler matrix that used to feed a Magneto-electric (ME) dipole antenna array. As a result, a 2-D scanning antenna array with a compact size, wide bandwidth, and high radiation efficiency larger than84%isachieved. Furthergainenhancementof5dBiisachievedthroughdeployinga hybridgainenhancementtechniqueincludingAMCmushroomshapesaroundtheantenna array with a dielectric superstrate located in the broadside direction. The proposed scanning antenna array can be considered as a step toward the desired improvement in the data rate and coverage through enabling the space diversity for the communication link. The final activity is related to the development of high-gain wide-band mmWave antenna arrays for potential use in future mmWave applications. The first proposed configuration is a differential feeding circular polarized aperture antenna array implemented with PRGW technology. Differential feeding antenna designs offer more advantages than single- ended antennas for mmWave communications as they are easy to be integrated with differential mmWave monolithic ICs that have high common-mode rejection ratio providing an immunity of the environmental noise. The proposed differential feeding antenna array is designed and fabricated, which featured with a stable high gain and a high radiation efficiency over a wide bandwidth. Another proposed configuration is a dualpolarized ME-dipole PRGW antenna array for mmWave wireless communication. Dual polarizationisconsideredoneofthemostimportantantennasolutionsthatcansavecosts and space for modern communication systems. In addition, it is an effective strategy for multiple-input and multiple-output systems that can reduce the size of multiple antennas systems by utilizing extra orthogonal polarization. The proposed dual- polarized antenna array is designed to achieve a stable gain of 15 ± 1 dBi with low cross- polarization less than -30 dB over a wide frequency range of 20 % at 30 GHz

UWB Technology

Ultra Wide Band (UWB) technology has attracted increasing interest and there is a growing demand for UWB for several applications and scenarios. The unlicensed use of the UWB spectrum has been regulated by the Federal Communications Commission (FCC) since the early 2000s. The main concern in designing UWB circuits is to consider the assigned bandwidth and the low power permitted for transmission. This makes UWB circuit design a challenging mission in today's community. Various circuit designs and system implementations are published in this book to give the reader a glimpse of the state-of-the-art examples in this field. The book starts at the circuit level design of major UWB elements such as filters, antennas, and amplifiers; and ends with the complete system implementation using such modules

Recent developments of reconfigurable antennas for 4G and 5G wireless communications: A survey

YesReconfigurable antennas play important roles in smart and adaptive systems and are the subject of many research studies. They offer several advantages such as multifunctional capabilities, minimized volume requirements, low front-end processing efforts with no need for a filtering element, good isolation, and sufficient out-ofband rejection; these make them well suited for use in wireless applications such as fourth generation (4G) and fifth generation (5G) mobile terminals. With the use of active materials such as microelectromechanical systems (MEMS), varactor or p-i-n (PIN) diodes, an antenna’s characteristics can be changed through altering the current flow on the antenna structure. If an antenna is to be reconfigurable into many different states, it needs to have an adequate number of active elements. However, a large number of high-quality active elements increases cost, and necessitates complex biasing networks and control circuitry. We review some recently proposed reconfigurable antenna designs suitable for use in wireless communications such as cognitiveratio (CR), multiple-input multiple-output (MIMO), ultra-wideband (UWB), and 4G/5G mobile terminals. Several examples of antennas with different reconfigurability functions are analyzed and their performances are compared. Characteristics and fundamental properties of reconfigurable antennas with single and multiple reconfigurability modes are investigated.European Union’s Horizon 2020 research and innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET-722424