A Review on Different Techniques of Mutual Coupling Reduction Between Elements of Any MIMO Antenna. Part 2: Metamaterials and Many More

This two‐part article presents a review of different techniques of mutual coupling (MC) reduction. MC reduction is a primary concern while designing a compact multiple‐input‐multiple‐output (MIMO) antenna where the separation between the antennas is less than λ0/2, that is, half of the free‐space wavelength. The negative permittivity and permeability of artificially created materials/structures (Metamaterials) significantly help reduce MC among narrow‐band compact MIMO antenna design elements. In this part two of the review paper, we will discuss techniques: Metamaterials; Split‐Ring‐Resonator; Complementary‐Split‐Ring‐Resonator; Frequency Selective Surface, Metasurface, Electromagnetic Band Gap structure, Decoupling and Matching network, Neutralization line, Cloaking Structures, Shorting vias and pins and few more

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

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

Dual Band Slotted Printed Circular Patch Antenna With Superstrate and EBG Structure for 5G Applications

Slotted circular printed layered patch antenna is designed, simulated and fabricated for 5G (Fifth Generation) wireless communication applications. The antenna consists of slots in the main radiating circular patch element for miniaturizing the size of the radiating element and providing dual band radiation characteristics. The feed line is separated on bottom substrate layer with EBG (Electromagnetic Band-Gap) embedded for enhancing the gain characteristics of the antenna. Superstrate layer is also used for improving the gain of the antenna where the distance from the radiating antenna element is optimized for maximizing the impedance bandwidth and radiation characteristics. The feed realization and impedance matching of the radiating slotted circular patch antenna is done by inducing slot at the middle ground plane of the slot embedded circular patch antenna system. The proposed configuration provides power radiation gain values of more than 5 dB for the Ka band of communications, whereas the impedance bandwidth of the antenna is verified for the dual resonances at 27.5 and 28.5 GHz. Dual band radiation characteristics are attained by embedding and optimizing the slot length and width in the circular patch radiator element that is placed on the upper face of the substrate RT Rogers Duroid 5880 layer. The length of the microstrip feed line embedded in the lower layer of the substrate is optimized for providing required bandwidth characteristics for the dual frequency point radiations. The antenna configuration is designed, modeled and simulated in CST (Central Standard Time) Microwave studio. The antenna is fabricated and measured vs simulated frequency response, gain patterns and current density plots are presented for the verification of antenna operation in the desired frequency bands

Recent Advances in Antenna Design for 5G Heterogeneous Networks

The aim of this book is to highlight up to date exploited technologies and approaches in terms of antenna designs and requirements. In this regard, this book targets a broad range of subjects, including the microstrip antenna and the dipole and printed monopole antenna. The varieties of antenna designs, along with several different approaches to improve their overall performance, have given this book a great value, in which makes this book is deemed as a good reference for practicing engineers and under/postgraduate students working in this field. The key technology trends in antenna design as part of the mobile communication evolution have mainly focused on multiband, wideband, and MIMO antennas, and all have been clearly presented, studied and implemented within this book. The forthcoming 5G systems consider a truly mobile multimedia platform that constitutes a converged networking arena that not only includes legacy heterogeneous mobile networks but advanced radio interfaces and the possibility to operate at mm wave frequencies to capitalize on the large swathes of available bandwidth. This provides the impetus for a new breed of antenna design that, in principle, should be multimode in nature, energy efficient, and, above all, able to operate at the mm wave band, placing new design drivers on the antenna design. Thus, this book proposes to investigate advanced 5G antennas for heterogeneous applications that can operate in the range of 5G spectrums and to meet the essential requirements of 5G systems such as low latency, large bandwidth, and high gains and efficiencies

Design and SAR analysis of wearable antenna on various parts of human body, using conventional and artificial ground planes

This paper presents design and specific absorption rate analysis of a 2.4 GHz wearable patch antenna on a conventional and electromagnetic bandgap (EBG) ground planes, under normal and bent conditions. Wearable materials are used in the design of the antenna and EBG surfaces. A woven fabric (Zelt) is used as a conductive material and a 3 mm thicker Wash Cotton is used as a substrate. The dielectric constant and tangent loss of the substrate are 1.51 and 0.02 respectively. The volume of the proposed antenna is 113×96.4×3 mm3. The metamaterial surface is used as a high impedance surface which shields the body from the hazards of electromagnetic radiations to reduce the Specific Absorption Rate (SAR). For on-body analysis a three layer model (containing skin, fats and muscles) of human arm is used. Antenna employing the EBG ground plane gives safe value of SAR (i.e. 1.77W/kg2W/kg). The efficiency of the EBG based antenna is improved from 52 to 74%, relative to the conventional counterpart. The proposed antenna can be used in wearable electronics and smart clothing

Design and Analysis of Compact Antenna for 5G Communication Devices

A novel slotted rectangular patch antenna for E and W band, which resonates at the frequency of 67 GHz and has impedance bandwidth of 13.2 GHz, is used for resolving the issues of compactness, gain and efficiency of antenna designs for future generation 5G devices such as watches, and dongles. The single element antenna, having a dimension of 5.5 × 4.7 × 0.381 mm3, with a realized gain of 8.9 dBi was achieved. A rectangular slot was placed in the ground plane, just under the feed line of a microstrip patch antenna (MSPA), and this works as a defected ground structure (DGS): this improved the gain by up to 2 dB in the proposed design. The partial ground is used for tuning the impedance bandwidth. The rationale for the DGS, the partial ground, and the effect of the slot technique are discussed and implemented in this paper

Realizing uwb antenna array with dual and wide rejection bands using metamaterial and electromagnetic bandgaps techniques

This research article describes a technique for realizing wideband dual notched functionality in an ultra-wideband (UWB) antenna array based on metamaterial and electromagnetic bandgap (EBG) techniques. For comparison purposes, a reference antenna array was initially designed comprising hexagonal patches that are interconnected to each other. The array was fabricated on standard FR-4 substrate with thickness of 0.8 mm. The reference antenna exhibited an average gain of 1.5 dBi across 5.25-10.1 GHz. To improve the array's impedance bandwidth for application in UWB systems metamaterial (MTM) characteristics were applied it. This involved embedding hexagonal slots in patch and shorting the patch to the ground-plane with metallic via. This essentially transformed the antenna to a composite right/left-handed structure that behaved like series left-handed capacitance and shunt left-handed inductance. The proposed MTM antenna array now operated over a much wider frequency range (2-12 GHz) with average gain of 5 dBi. Notched band functionality was incorporated in the proposed array to eliminate unwanted interference signals from other wireless communications systems that coexist inside the UWB spectrum. This was achieved by introducing electromagnetic bandgap in the array by etching circular slots on the ground-plane that are aligned underneath each patch and interconnecting microstrip-line in the array. The proposed techniques had no effect on the dimensions of the antenna array (20 mm x 20 mm x 0.87 mm). The results presented confirm dual-band rejection at the wireless local area network (WLAN) band (5.15-5.825 GHz) and X-band satellite downlink communication band (7.10-7.76 GHz). Compared to other dual notched band designs previously published the footprint of the proposed technique is smaller and its rejection notches completely cover the bandwidth of interfering signals

Design of a Dual Band SNG Metamaterial Based Antenna for LTE 46/WLAN and Ka-Band Applications

The non-existing properties of the metamaterial surfaces can be utilized to improve the antenna radiation characteristics. In this article, a design and performance analysis of a Single Negative (SNG) metamaterial based antenna is imparted for LTE 46/WLAN and Ka-band (like in satellite communication for the receiving side) applications. The unit cell of the metamaterial surface exhibits negative permittivity and positive permeability; yielding a high magnitude positive refractive index, is used to improve and analyze the performance of the proposed monopole antenna element. The proposed SNG based antenna covers a -10 dB bandwidth from 5.35-5.69 GHz (LTE 46/WLAN) and 17.81-20.67 GHz (Ka-band). The total size of the proposed antenna element is 20.2 x 28 .4 mm(2) while a 2 x 3 SNG metamaterial surface is used at the back of the antenna element which improves the gain from 4.52 dB to 9.13 dB for the desired Ka band and 1.17 to 5.04 dB for the LTE 46/WLAN band. Furthermore, for the LTE 46/WLAN frequency band, the impedance matching also gets better, resulting in the return loss improvement from -11 dB to -32.4 dB. Moreover, the radiation efficiency is also improved by more than 10 % for the Ka band after employing the SNG metamaterial surface. The measured results fall in good agreement with the simulated one and make the proposed SNG metamaterial based antenna design competent for the LTE 46/WLAN and Ka-band (like in satellite communication for the receiving side) applications