“Onsite” and “Virtual” September 28th ~ 30th, 2023, tuit, Tashkent, Uzbekistan Almaty University of Power Engineering and Telecommunications named after G. Daukeyev

Kozhakhmetova Bagdat | 3:15 PM
Beibit Karibayev, Katipa Chezhimbayeva, Dilmurod Davronbekov
The Usage of Fractal Antennas in Wireless Communication Systems
International Conference on Information Science and Communications Technologies ICISCT 2023
“Onsite” and “Virtual” September 28th ~ 30th, 2023, TUIT, Tashkent, Uzbekistan
Almaty University of Power Engineering and Telecommunications named after G.Daukeyev

Introduction

In many ways, the effectiveness of the antenna depends on the quantity and quality of the transmitted and received information in the system, so the role of antenna systems in radio communication is quite large.
Antenna - is the most important and necessary element of any radio system.

Fractal antennas

Fractal antennas largely satisfy these requirements. The principle of fractal antennas is based on the use of fractal geometry and the property of self-similarity, suggesting a similar division of the curve or similar segments of the figure of the active part of the antenna
To date, there are a diverse number of antennas used in wireless communications. One of the main requirements for modern antennas is miniaturization (compactness), multi-band and broadband.
Koch's Snowflake
Serpinsky Triangle

Fractal structures in mobile communications

The development of a hexagonal fractal antenna with a lateral power supply system is presented in [11]. The operating frequency of the antenna is 4.2 GHz and has a compact size of 23 mm × 27.5 mm. Figure 1 shows the prototype of the developed antenna.
According to the simulation results and experimental measurements, this antenna showed good antenna matching (SWR less than 2 for the total operating frequency range from 3.6 to 23 GHz with a bandwidth of 19.4 GHz), as well as gain and directional pattern.
Fig.1 - The prototype of a hexagonal fractal antenna [11]
In work [15] presents the development of a planar fractal antenna array for 5G applications. The antenna design is shown in Figure 2. The antenna demonstrates a wide impedance band from 22.28 GHz to 33 GHz and provides peak gain and radiation efficiency of 10.7 dBi and 95%.
Fig 2 - The constuction of the fractal antenna array [15]
Ansys HFSS (High Frequency Structure Simulator)
CST Microwave Studio
AWR Microwave Office
EMSS FEKO
Matlab
Computer simulation of microwave devices

Antenna design

MIMO 2x2 antenna patch based on the anisotropic Zhanabaev fractal of the first iteration. An epoxy FR-4 substrate was used for the substrate material. Its dielectric constant is 4.4, and the thickness of the substrate is 1.6 mm. Figure 3 shows a 2x2 MIMO patch antenna model made in the Ansys HFSS microwave device simulation program
The simulation results of parameter S11 are shown in Figure 4. The resonant frequencies are 2.13 GHz, 2.91 GHz. The SWR value is 3. For better matching of the antenna, it is necessary to change the parameters of the thickness of the lines and the power supply circuit.
S11 parameter
2x2 MIMO patch antenna model

Antenna design

The traditional MIMO antenna shown in Figure 5. The antenna consists of a grid of 4 elements and resonates at frequencies of 1.9GHz and 3.6GHz
1x4 MIMO patch antenna model
S11 parameter
SWR parameter
The reflection coefficient (S11 parameter) and SWR are among the main characteristics of the antenna. SWR is also used to evaluate the effectiveness of antenna radiation. A high SWR indicates poor alignment of the antenna and the transmission line.

Conclusion

This work discusses fractal antennas and the possibility of their use in wireless communication, in particular mobile communication systems of new generations. A literature review has shown that fractal antennas are relevant today and have such advantages as: miniaturization, compactness, multi-band, broadband, which fully meets the requirements for modern antenna systems. However, in this direction, it is still necessary to conduct a number of studies related to signal processing, the creation of phased antenna arrays based on fractal structures and the study of mutual influence between the elements of the antenna system.