scholarly journals On the 5G Communications: Fractal-Shaped Antennas for PPDR Applications

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Mihai-Virgil Nichita ◽  
Maria-Alexandra Paun ◽  
Vladimir-Alexandru Paun ◽  
Viorel-Puiu Paun
Keyword(s):  
Standing Wave ◽  
High Performance ◽  
Disaster Relief ◽  
Dipole Antenna ◽  
Voltage Standing Wave Ratio ◽  
Antenna Design ◽  
Dipole Antennas ◽  
Self Similarity ◽  
Optimum Operation ◽  
Fractal Antennas

In this study, one method of using antennas based on fractals to cover few kinds of public protection and disaster relief (PPDR) communications was presented. Dedicated antenna forms, necessary for antenna design by 5G implementation, were enhanced to suit the requirements of specific applications. Employing fractal-shaped antennas have allowed us to accomplish all these actions, which request compact, conformal, and broadband high performance devices. Antennas derived from Koch’s curve fractals are studied. In order to implement PPDR communications in 5G technology, frequency bandwidths of importance have been carefully selected and properly included in the antenna developments under MATLAB environment. Important information necessary for antenna designers, such as 360 degrees directivity at various frequencies, the impedance (resistance and reactance) along the bandwidth of interest, as well as voltage standing wave ratio (VSWR) along the bandwidth of interest for dipole, one-iteration, and two-iteration Koch’s curves, respectively, have been obtained. The characteristic of directivity at selected frequencies is also highlighted. In order to maximize antenna parameters, this study has successfully proposed using fractal antennas, objects that use self-similarity property of fractals for optimum operation in several frequency ranges. For the studied antennas, we have obtained the following results regarding the maximum gains in dBi (which is the unit of the ratio between the gains of the antenna compared to the gain of an isotropic antenna). For the dipole antennas, the gains are 2.73 dBi and 4.76 dBi at 460 MHz and 770 MHz, respectively. The gains for one-iteration fractal Koch antenna are 6.91 dBi and 4.51 dBi at 460 MHz and 770 MHz, respectively, and finally, for two-iteration fractal Koch antenna, the gains are 4.91 dBi and 3.28 dBi at 460 MHz and 770 MHz, respectively. Moreover, the impedance along the bandwidth is approximately 360 Ohms for two-iteration fractal Koch antenna, 180 Ohms for one-iteration fractal Koch antenna, and 140 Ohms for dipole antenna, respectively.

A NEW MEASURE OF LACUNARITY FOR GENERALIZED FRACTALS AND ITS IMPACT IN THE ELECTROMAGNETIC BEHAVIOR OF KOCH DIPOLE ANTENNAS

Fractals ◽  
2006 ◽  
Vol 14 (04) ◽  
pp. 271-282 ◽  
Author(s):  
KAUSHIK SENGUPTA ◽  
K. J. VINOY
Keyword(s):  
Spatial Distribution ◽  
Fractal Dimension ◽  
Antenna Design ◽  
Complex Nature ◽  
Dipole Antennas ◽  
Science And Engineering ◽  
Fractal Set ◽  
Final Goal ◽  
Electromagnetic Behavior ◽  
Fractal Antennas

In recent years, fractal geometries have been explored in various branches of science and engineering. In antenna engineering several of these geometries have been studied due to their purported potential of realizing multi-resonant antennas. Although due to the complex nature of fractals most of these previous studies were experimental, there have been some analytical investigations on the performance of the antennas using them. One such analytical attempt was aimed at quantitatively relating fractal dimension with antenna characteristics within a single fractal set. It is however desirable to have all fractal geometries covered under one framework for antenna design and other similar applications. With this objective as the final goal, we strive in this paper to extend an earlier approach to more generalized situations, by incorporating the lacunarity of fractal geometries as a measure of its spatial distribution. Since the available measure of lacunarity was found to be inconsistent, in this paper we propose to use a new measure to quantize the fractal lacunarity. We also demonstrate the use of this new measure in uniquely explaining the behavior of dipole antennas made of generalized Koch curves and go on to show how fundamental lacunarity is in influencing electromagnetic behavior of fractal antennas. It is expected that this averaged measure of lacunarity may find applications in areas beyond antennas.

Transient radiation from an unloaded, finite dipole antenna in a borehole: Experimental and numerical results

Geophysics ◽  
2005 ◽  
Vol 70 (6) ◽  
pp. K43-K51 ◽  
Author(s):  
Sixin Liu ◽  
Motoyuki Sato
Keyword(s):  
Dipole Antenna ◽  
Antenna Design ◽  
Dipole Antennas ◽  
Radiation Characteristics ◽  
Resonant Frequencies ◽  
High Frequencies ◽  
Waveform Distortion ◽  
Directivity Patterns ◽  
Homogeneous Media ◽  
Difference Time

Dipole antennas in boreholes are used for tomographic imaging or electromagnetic well logging. A cylindrically layered structure within the borehole will change the radiation characteristics of a dipole antenna. Our objective is to understand the effects of the borehole structure upon the impedance, waveform distortion, and directivity patterns of a dipole antenna. We use a finite-difference, time-domain (FDTD) technique to simulate borehole-antenna radiation, while the geometry of both the dipole and the borehole are modeled with a subgrid technique. The simulated input impedances are verified by experimental results. Both the water-filled and the air-filled boreholes distort the radiated wavefronts, waveforms, and resonant frequencies relative to the same characteristics of a dipole in homogeneous media. A water-filled borehole lowers the first resonant frequency, while an air-filled borehole raises it. At high frequencies, the antenna in the water-filled borehole exhibits radiation side lobes. The borehole effects for water- and air-filled boreholes differ and should not be neglected for borehole antenna design.

Perbandingan Desain Antena Dipole dan Yagi-Uda Menggunakan Material Aluminium pada Frekuensi 470 – 890 MHz

2017 ◽  
Vol 3 (3) ◽  
pp. 140
Author(s):  
Suci Rahmatia ◽  
Putri Wulandari ◽  
Nurul Khadiko ◽  
Fitria Gani Sulistya
Keyword(s):  
Radiation Pattern ◽  
Daily Activity ◽  
Dipole Antenna ◽  
Antenna Gain ◽  
Communication Tool ◽  
Dipole Antennas ◽  
Gain Bandwidth ◽  
Large Gain ◽  
At Home

<p><em>Abstrak </em><strong> - Antena merupakan alat pemancar yang akrab dengan aktifitas sehari-hari dan mudah sekali dijumpai, di rumah, di gedung, bahkan pada alat komunikasi yang digunakan. Salah satu antena yang sering digunakan adalah antena televisi. Antena televisi yang sering digunakan adalah Yagi-Uda yang biasanya dipakai sebagai outdoor antena dan antena dipole yang biasanya digunakan untuk indoor antena. Masing – masing jenis antena memiliki kriteria dan keuntungan berdasarkan dari kebutuhan penggunaannya. Baik antena dipole maupun antena Yagi-Uda memiliki perbedaan diantaranya adalah besar bandwidth, nilai gain, dan pola radiasi. Pada paper ini dapat diketahui bahwa bandwidth yang dimiliki antena yagi-uda lebih besar daripada antena dipole yakni 0.39943 MHz untuk antena yagi-uda dan 0.16569 MHz untuk antena dipole. Begitupula dengan besar Gain yang dimiliki antena Yagi-Uda (6.64 dBi) lebih besar dibandingkan dengan gain dari antena dipole (2.29 dBi). Perbedaan ini dikarenakan faktor elemen director dan ketebalannya.</strong></p><p><strong><br /></strong></p><p><strong><em>Kata Kunci</em></strong> – <em>Atena Televisi, Atena Yagi-Uda, Atena Dipole, Gain, Bandwidth</em></p><p><em> </em></p><p><em>Abstract</em> <strong>- Antenna is a transmitter tool that is familiar with daily activity and easy to find at home, in the building, even on the communication tool used. One of antenna that is often used is a television antenna. Television antennas are often used is Yagi-Uda which is usually used as an outdoor antenna and dipole antenna that is usually used for indoor antennas. Each type of antenna has the criteria and advantages based on the needs of its use. Both dipole antennas and Yagi-Uda antennas have differences among them are bandwidth, gain, and radiation pattern. In this paper it can be seen that the bandwidth of yagi-uda antenna is bigger than dipole antenna that is 0.39943 MHz for Yagi-Uda antenna and 0.16569 MHz for dipole antenna. Neither the large Gain of the Yagi-Uda antenna (6.64 dBi) is greater than the gain of the dipole antenna (2.29 dBi). This difference is due to element factor of director and its thickness.</strong></p><p><strong><br /></strong></p><p><strong><em>Keywords</em></strong><strong> – </strong><em>Television Antenna, Yagi-Uda Antenna, Dipole Antenna, Gain, Bandwidth</em><strong> </strong></p>

Investigation of e-textile dipole antenna performance based on embroidery parameters

2021 ◽  
pp. 004051752110134
Author(s):  
Daniel Agu ◽  
Rachel J Eike ◽  
Allyson Cliett ◽  
Dawn Michaelson ◽  
Rinn Cloud ◽  
...  
Keyword(s):  
Frequency Band ◽  
Impedance Matching ◽  
Dipole Antenna ◽  
Water Soluble ◽  
Wearable Sensor ◽  
Dipole Antennas ◽  
Antenna Performance ◽  
Large Production ◽  
Lower Transmission ◽  
The Ideal

E-textile antennas have the potential to be the premier on-body wearable sensor. Embroidery techniques, which can be applied to produce e-textile antennas, assist in large production volumes and fast production speeds. This paper focuses on the effects of three commonly used embroidery parameters, namely stitch type, conductive thread location, and stabilizer, on the performance of embroidered dipole antennas in order to determine the ideal embroidery combination for optimal antenna performance. Fifty-four dipole antenna samples were fabricated and measured at the industrial, scientific, and medical (ISM) frequency band of 2.45 GHz. The results of this study show that machine-embroidered antenna designs with satin stitches resonate at a lower frequency and exhibit a lower transmission gain compared with those made with contour stiches, and the conductive thread location in the bobbin location plus the use of a water-soluble stabilizer can help improve impedance matching.

Design of Antipodal Vivaldi Antenna Array

2013 ◽  
Vol 380-384 ◽  
pp. 3465-3468
Author(s):  
Hai Bo Tang ◽  
Xiao Zhong Shui
Keyword(s):  
Antenna Array ◽  
Standing Wave ◽  
Voltage Standing Wave Ratio ◽  
Radiation Characteristics ◽  
Vivaldi Antenna ◽  
Cross Structure ◽  
Structure Array

Firstly in this paper,an antipodal Vivaldi antenna is designed.The bandwidth is from 6GHz to 18GHz. The simulated results show good electric performance and the voltage standing wave ratio is less than 2 in the whole bandwidth.Secondly depending on this unit,this paper designs two kinds of arrays and estimates their radiation characteristics,respectively.The one array is a 1×8 array and the another array is a X-cross structure array with four elements.

THEORY AND DESIGN OF A COAXIAL SUPPORTING BEAD MADE OF COMPOSITE DIELECTRICS

1961 ◽  
Vol 39 (6) ◽  
pp. 926-934
Author(s):  
Gilbert H. Owyang
Keyword(s):  
Standing Wave ◽  
Frequency Ratio ◽  
Low Voltage ◽  
Coaxial Line ◽  
Wide Band ◽  
Voltage Standing Wave Ratio ◽  
Physical Parameters ◽  
Minimum Frequency ◽  
Typical Design

The effect due to the presence of a single supporting bead made of composite dielectrics in a coaxial line is being studied. A formula correlating the standing wave ratio caused by the bead and the physical parameters of the bead is derived. A bead of this type may be designed to have very low voltage standing wave ratio (VSWR) over a very wide band of frequency. A typical design using quartz and air as dielectrics is given, and the calculated VSWR is below 1.003 over a bandwidth whose maximum to minimum frequency ratio is as high as 13:1.

Embroidery Leaf Shape Dipole Antenna Performances and Characterisation

2017 ◽  
Vol 7 (3) ◽  
pp. 1467
Author(s):  
N. J. Ramly ◽  
M. K. A. Rahim ◽  
N. A. Samsuri ◽  
H. A. Majid
Keyword(s):  
Return Loss ◽  
Leaf Shape ◽  
Dipole Antenna ◽  
Antenna Design ◽  
Operating Frequency ◽  
Ism Band ◽  
Textile Antenna ◽  
Different Types

In this paper, leaf shape textile antenna in ISM band has been chosen to study. The operating frequency of the dipole antenna is 2.45GHz. The effect of conductive threads with three different types of sewing has been analysed. The first type of sewing leaf shape dipole antenna is to stitch around itself and embroidered into a fleece fabric with circular follow by vertical and horizontal stitch respectively. From measured return loss, the antenna with circular stitch shows better performances with optimum resonances compared with the two types of stitching. The measured results confirm that the circular stitch is more suitable for leaf shape dipole antenna design. Thus it can be concluded that different stitch gives different results for leaf shape dipole antenna.

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