scholarly journals Performance analysis of first iteration koch curve fractal log periodic antenna of varying flare angles

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Ashutosh Singh ◽  
Reneez Kabeer ◽  
Z. Ali ◽  
V. Singh ◽  
M. Shukla

AbstractMiniaturization has always been a crucial challenge in the field of antenna engineering. In the recent past a number of researchers have shown that fractal geometry have potential to design smaller, broad band and multi band antennas. In this proposed work performances of log periodic fractal antennas of different flare angles have been investigated. Simulation results show that fractal log periodic antenna gives better performance in terms of gain, return loss and directivity. Performance of log periodic fractal antenna has also been investigated for flare angles 30°, 45°, 60°, 70° and 80°. In this proposed work fractal antenna gives best performance with 60° flare angle.

2019 ◽  
Vol 11 (1) ◽  
pp. 159-172
Author(s):  
Pablo Lupera Morillo ◽  
Gary Flores Cadena ◽  
Ricardo Merizalde

Purpose – In this research paper, the electrical and radiation characteristics of a proposed fractal antenna based on the Koch curve in the second iteration for reception of digital terrestrial television signals are designed and analyzed by laboratory tests. Methodology/approach/design – The design is based on the concepts of fractal geometry and on a previously designed antenna, which is adapted to obtain a different frequency of operation; the designed antenna is constructed in three different ways, finally, they are tested in the lab using vector-network-analyzer, that allows to measure parameters, such as: VSWR, gain and radiation pattern. Findings – The fractal antenna based on the Koch curve has the necessary characteristics to receive digital terrestrial television signals in the UHF band.


2015 ◽  
Vol 37 ◽  
pp. 334
Author(s):  
Masoud Khoubroo Eslamloo ◽  
Pejman Mohammadi

In this letter a novel broad band substrate integrated waveguide (SIW) power divider is proposed. It consist of four output channels made by SIW with equal length and equal width. Design equations and process are given with mathematical analysis. The propagation constant of the output signals have been adjusted by utilize only four via in the middle of the output arms. As a result a novel equal output power divider, is obtained accordingly. The experimental results of a prototype at 10 GHz shows 3.1 GHz bandwidth in both simulation and measurement results. Return loss and transmission coefficients have good agreement with simulation results in considered band.


Author(s):  
Anirban Karmakar

Abstract In mathematical definition, a fractal is a self-similar subset of Euclidean space whose fractal dimension strictly exceeds its topological dimension which in turn involves a recursive generating methodology that results in contours with infinitely intricate fine structures. Fractal geometry has been used to model complex natural objects such as clouds coastlines, etc., that has space-filling properties. In the past years, several groups of scientists around the globe tried to implement the structure of fractal geometry for applications in the field of electromagnetism, which led to the development of new innovative antenna configurations called “fractal antennas” which is primarily focused in fractal antenna elements, and fractal antenna arrays. It has been demonstrated that by exploiting the recursive nature of fractals, several marvellous kinds of properties can be observed in antennas and arrays. The primary focus of this article is to provide a compressed overview of the developments in fractal-shaped antennas as well as arrays over the last few decades where the most prominent contributions mostly from IEEE journals have been highlighted. The open intention of this review work is to show an encouraging path to antenna researchers for its advancement using fractal geometries.


Author(s):  
Amer T. Abed ◽  
Mahmood J. Abu-AlShaer ◽  
Aqeel M. Jawad

When the length of the antenna is less than a quarter of the wavelength of the operating frequency, good radiation properties are difficult to obtain. However, size limitations can be overcome in this case using a fractal geometry antenna. The shape is repeated in a limited size such that the total length of the antenna is increased to match, for example, half of the wavelength of the corresponding desired frequency. Many fractal geometries, e.g., the tree, Koch, Minkowski, and Hilbert fractals, are available. This chapter describes the details of designing, simulations, and experimental measurements of fractal antennas. Based on dimensional geometry in terms of desired frequency bands, the characteristics of each iteration are studied carefully to improve the process of designing the antennas. In depth, the surface current distribution is investigated and analyzed to enhance the circular polarization radiation and axial ratio bandwidth (ARBW). Both, simulation and experimental, results are discussed and compared. Two types of fractal antennas are proposed. The first proposed fractal antenna has a new structure configured via a five-stage process. The second proposed fractal antenna has a low profile, wherein the configuration of the antenna was based on three iterations.


2021 ◽  
Vol 2062 (1) ◽  
pp. 012004
Author(s):  
Gudla Ramalakshmi ◽  
P Mallikarjuna Rao

Abstract The rapid advancements in wireless technology desires compact, miniaturized, multiband and ultra wideband antennas. Fractal antennas have been proved as a source for fulfilling these demands. In this paper a 2nd order Koch fractal antenna of size 29.6 × 35.7mm2 designed on FR4-epoxy substrate material of dielectric constant (ɛr) 4.4 with a height of 1.6mm. This antenna is named as ANTENNA-1. To increase this antenna’s performance a meta material unit cell has been placed on the ground plane to serve multi band applications and is named as ANTENNA-2, which is the proposed antenna in this paper. The simulations have been carried out for both the antennas using ANSYS HFSS tool over the frequency sweep of (1-12GHz). The simulation results of proposed antenna producing 7 frequency bands which serves Wi-Fi, WLAN, C-band, and X band wireless communications. The simulation results like return loss, VSWR values have a good matching with the measured return loss, VSWR results of the fabricated antenna


2013 ◽  
Vol 330 ◽  
pp. 957-960
Author(s):  
Qiao Ling Du ◽  
Zhi Rui Wang ◽  
Yu Pei ◽  
Yi Ding Wang

This paper investigates the performance analysis of OQPSK in HF band for wireless sensor networks. An analytical model for getting symbol error rate (SER) is given in presence of Bi-Kappa noise in HF band. And the SER of OQPSK is given in AWGN and Rayleigh fading channel. Simulation results HF noise as Bi-Kappa noise should be investigated in HF band for WSN.


2013 ◽  
Vol 846-847 ◽  
pp. 1185-1188 ◽  
Author(s):  
Hua Bing Wu ◽  
Jun Liang Liu ◽  
Yuan Zhang ◽  
Yong Hui Hu

This paper proposes an improved acquisition method for high-order binary-offset-carrier (BOC) modulated signals based on fractal geometry. We introduced the principle of our acquisition method, and outlined its framework. We increase the main peak to side peaks ratio in the BOC autocorrelation function (ACF), with a simple fractal geometry transform. The proposed scheme is applicable to both generic high-order sine-and cosine-phased BOC-modulated signals. Simulation results show that the proposed method increases output signal to noise ratio (SNR).


2016 ◽  
Vol 09 (03) ◽  
pp. 1650045 ◽  
Author(s):  
Mianmian Zhang ◽  
Yongping Zhang

Lotka–Volterra population competition model plays an important role in mathematical models. In this paper, Julia set of the competition model is introduced by use of the ideas and methods of Julia set in fractal geometry. Then feedback control is taken on the Julia set of the model. And synchronization of two different Julia sets of the model with different parameters is discussed, which makes one Julia set change to be another. The simulation results show the efficacy of these methods.


Author(s):  
Shweta Rani ◽  
Sushil Kakkar

This paper focuses on the design and development of modified Koch fractal antenna. Compared to traditional Koch curve antenna, the presented antenna possesses a greater number of frequency bands and better impedance matching. Furthermore, the bacterial foraging optimization (BFO) approach is implemented to enhance the impedance bandwidth. The developed technique has been verified by employing various numerical simulations. The design parameters generated from the optimization procedure have been utilized to manufacture the antenna and the respective experimental and simulated results compared. The measured results show that the designed antenna exhibits multi and wideband behavior, covering WLAN, WIMAX, and various other wireless applications.


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