DESIGNING A MIMO ANTENNA ARRAY FOR 5G NETWORKS

2021 ◽  
pp. 99-105
Author(s):  
К.А. Бердников ◽  
Е.А. Ищенко ◽  
В.В. Кузнецова ◽  
С.М. Фёдоров
Keyword(s):  
Antenna Array ◽  
Antenna System ◽  
Distribution Functions ◽  
Cumulative Distribution ◽  
Radio Waves ◽  
Mimo Antenna ◽  
Cumulative Distribution Functions ◽  
Fifth Generation ◽  
Radiated Power ◽  
Wave Radio

Рассматривается антенная система для сетей пятого поколения частот 37 ГГц (миллиметровый диапазон радиоволн). Предлагается установка антенны на задней стенке устройства, а излучение радиоволн происходит через стеклянную заднюю панель устройства. Для функционирования в сетях пятого поколения была разработана MIMO антенная решетка, которая состоит из четырех элементов и способна функционировать в «умном» режиме. Благодаря этому возможно формирование луча в антенной системе (beamforming). Для анализа характеристик антенной системы были получены коэффициенты корреляции огибающей, диаграммы направленности, картины электрических полей, получены зависимости эффективной изотропно излучаемой мощности (EIRP), построены графики кумулятивных функций распределения EIRP в линейном и логарифмическом масштабе. Для определения влияния излучения на человека были построены картины удельного коэффициента поглощения (SAR) в соответствии с европейскими нормами на 10 грамм тканей. Все полученные результаты показывают высокую эффективность разработанной конструкции антенной решетки для сетей пятого поколения. Антенные элементы обладают малой взаимной корреляцией, позволяют обеспечить формирование луча, кумулятивные функции распределения показывают высокий уровень покрытия сферы эффективной изотропно излучаемой мощности радиоволнами. Также было показано, что разработанная антенная система обладает малым уровнем удельного коэффициента поглощения, что доказывает безопасность сетей пятого поколения миллиметрового диапазона радиоволн. Развитие современных систем связи позволяет достичь высокой безопасности и эффективности при получении информации The article discusses an antenna system for networks of the fifth generation of 37 GHz frequencies (millimeter-wave radio waves). We propose to install the antenna on the rear wall of the device, radio waves are emitted through the glass rear panel of the device. For functioning in networks of the fifth generation, a MIMO antenna array was developed, which consists of four elements and is capable of functioning in a "smart" mode. This makes it possible to form a beam in the antenna system (beamforming). To analyze the characteristics of the antenna system, we obtained the correlation coefficients of the envelope, directional patterns, patterns of electric fields, the dependences of the effective isotropically radiated power (EIRP), and we plotted the graphs of the cumulative distribution functions of EIRP on a linear and logarithmic scale. To determine the effect of radiation on a person, we built pictures of the specific absorption rate (SAR) in accordance with European standards for 10 grams of tissue. All the results obtained show the high efficiency of the developed design of the antenna array for fifth generation networks. Antenna elements have low cross-correlation, allow for beam formation, cumulative distribution functions show a high level of coverage of the sphere of effective isotropically radiated power by radio waves. We also show that the developed antenna system has a low level of specific absorption coefficient, which proves the safety of fifth-generation networks of millimeter-wave radio waves. The development of modern communication systems makes it possible to achieve high security and efficiency in obtaining information

scholarly journals Design of Multi-Mode Antenna Array for Use in Next-Generation Mobile Handsets

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2447
Author(s):  
Naser Ojaroudi Parchin ◽  
Haleh Jahanbakhsh Basherlou ◽  
Raed A. Abd-Alhameed
Keyword(s):  
Antenna Array ◽  
Ground Plane ◽  
Multiple Input Multiple Output ◽  
Antenna System ◽  
Cellular Systems ◽  
Good Efficiency ◽  
Mimo Antenna ◽  
Fifth Generation ◽  
Input Multiple Output ◽  
Multi Mode

In this study, a new design of a tri-band multiple-input–multiple-output (MIMO) antenna array is proposed for fifth-generation (5G) cellular systems. Its structure is composed of eight identical planar-inverted F antenna (PIFA) elements placed at different edge corners of the handset mainboard with overall dimensions of 150 × 75 mm2. The PIFA elements and ground plane of the MIMO antenna system are arranged on the back layer of the platform, which makes the design easy to integrate with the handset circuit. For S11 ≤ −10 dB, the radiation elements of the MIMO design operate at the frequency ranges of 2.5–2.7 GHz, 3.4–3.75 GHz, and 5.6–6 GHz covering the long-term evolution (LTE) 41, 42/43, and 47 operation bands, respectively. The array achieves better than 15 dB return loss results across the three operating bands. The presented antenna array not only exhibits multi-band operation but also generates the polarization diversity characteristic, which makes it suitable for multi-mode operation. The proposed antenna array was simulated and experimentally tested. Fundamental characteristics of the proposed design are investigated. It offers three band S-parameters with acceptable isolation and dual-polarized radiation with quite good efficiency and gain results. Besides this, the total active reflection coefficient (TARC) and envelope correlation coefficient (ECC) results of the PIFAs are very low over the bands. In addition, the radiation characteristics of the MIMO antenna in the presence of the user and handset components are studied. Moreover, a new and compact phased array millimeter-wave (MM-Wave) antenna with broad bandwidth and end-fire radiation is introduced which can be easily integrated into the smartphone antenna system. Due to its good performance and simple structures, the proposed smartphone antenna array design is a good candidate for future multi-mode 5G cellular applications.

scholarly journals A Graphene-Assembled Film Based MIMO Antenna Array with High Isolation for 5G Wireless Communication

2021 ◽  
Vol 11 (5) ◽  
pp. 2382
Author(s):  
Rongguo Song ◽  
Xiaoxiao Chen ◽  
Shaoqiu Jiang ◽  
Zelong Hu ◽  
Tianye Liu ◽  
...  
Keyword(s):  
Antenna Array ◽  
Antenna Arrays ◽  
Multiple Input Multiple Output ◽  
Frequency Selective Surface ◽  
Antenna System ◽  
Antenna Element ◽  
Mimo Antenna ◽  
High Isolation ◽  
Input Multiple Output ◽  
Alternative Material

With the development of 5G, Internet of Things, and smart home technologies, miniaturized and compact multi-antenna systems and multiple-input multiple-output (MIMO) antenna arrays have attracted increasing attention. Reducing the coupling between antenna elements is essential to improving the performance of such MIMO antenna system. In this work, we proposed a graphene-assembled, as an alternative material rather than metal, film-based MIMO antenna array with high isolation for 5G application. The isolation of the antenna element is improved by a graphene assembly film (GAF) frequency selective surface and isolation strip. It is shown that the GAF antenna element operated at 3.5 GHz has the realized gain of 2.87 dBi. The addition of the decoupling structure improves the isolation of the MIMO antenna array to more than 10 dB and corrects the antenna radiation pattern and operating frequency. The isolation between antenna elements with an interval of 0.4λ is above 25 dB. All experimental results show that the GAF antenna and decoupling structure are efficient devices for 5G mobile communication.

scholarly journals Application of Copula functions in statistics

2007 ◽  
Author(s):  
Αριστείδης Νικολουλόπουλος
Keyword(s):  
Discrete Data ◽  
Distribution Functions ◽  
Cumulative Distribution ◽  
Multivariate Distribution ◽  
Dependence Structure ◽  
Copula Models ◽  
Cumulative Distribution Functions ◽  
Multivariate Discrete Distributions ◽  
Dependence Properties ◽  
Multivariate Copula

Studying associations among multivariate outcomes is an interesting problem in statistical science. The dependence between random variables is completely described by their multivariate distribution. When the multivariate distribution has a simple form, standard methods can be used to make inference. On the other hand one may create multivariate distributions based on particular assumptions, limiting thus their use. Unfortunately, these limitations occur very often when working with multivariate discrete distributions. Some multivariate discrete distributions used in practice can have only certain properties, as for example they allow only for positive dependence or they can have marginal distributions of a given form. To solve this problem copulas seem to be a promising solution. Copulas are a currently fashionable way to model multivariate data as they account for the dependence structure and provide a flexible representation of the multivariate distribution. Furthermore, for copulas the dependence properties can be separated from their marginal properties and multivariate models with marginal densities of arbitrary form can be constructed, allowing a wide range of possible association structures. In fact they allow for flexible dependence modelling, different from assuming simple linear correlation structures. However, in the application of copulas to discrete data marginal parameters affect dependence structure, too, and, hence the dependence properties are not fully separated from the marginal properties. Introducing covariates to describe the dependence by modelling the copula parameters is of special interest in this thesis. Thus, covariate information can describe the dependence either indirectly through the marginalparameters or directly through the parameters of the copula . We examine the case when the covariates are used both in marginal and/or copula parameters aiming at creating a highly flexible model producing very elegant dependence structures. Furthermore, the literature contains many theoretical results and families of copulas with several properties but there are few papers that compare the copula families and discuss model selection issues among candidate copula models rendering the question of which copulas are appropriate and whether we are able, from real data, to select the true copula that generated the data, among a series of candidates with, perhaps, very similar dependence properties. We examined a large set of candidate copula families taking intoaccount properties like concordance and tail dependence. The comparison is made theoretically using Kullback-Leibler distances between them. We have selected this distance because it has a nice relationship with log-likelihood and thus it can provide interesting insight on the likelihood based procedures used in practice. Furthermore a goodness of fit test based on Mahalanobisdistance, which is computed through parametric bootstrap, will be provided. Moreover we adopt a model averaging approach on copula modelling, based on the non-parametric bootstrap. Our intention is not to underestimate variability but add some additional variability induced by model selection making the precision of the estimate unconditional on the selected model. Moreover our estimates are synthesize from several different candidate copula models and thus they can have a flexible dependence structure. Taking under consideration the extended literature of copula for multivariate continuous data we concentrated our interest on fitting copulas on multivariate discrete data. The applications of multivariate copula models for discrete data are limited. Usually we have to trade off between models with limited dependence (e.g. only positive association) and models with flexible dependence but computational intractabilities. For example, the elliptical copulas provide a wide range of flexible dependence, but do not have closed form cumulative distribution functions. Thus one needs to evaluate the multivariate copula and, hence, a multivariate integral repeatedly for a large number of times. This can be time consuming but also, because of the numerical approach used to evaluate a multivariate integral, it may produce roundoff errors. On the other hand, multivariate Archimedean copulas, partially-symmetric m-variate copulas with m − 1 dependence parameters and copulas that are mixtures of max-infinitely divisible bivariate copulas have closed form cumulative distribution functions and thus computations are easy, but allow only positive dependence among the random variables. The bridge of the two above-mentioned problems might be the definition of a copula family which has simple form for its distribution function while allowing for negative dependence among the variables. We define such a multivariate copula family exploiting the use of finite mixture of simple uncorrelated normal distributions. Since the correlation vanishes, the cumulative distribution is simply the product of univariate normal cumulative distribution functions. The mixing operation introduces dependence. Hence we obtain a kind of flexible dependence, and allow for negative dependence.

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