Synthesis of a Galile oand Wi-Max Three-Band Fractal-Eroded Patch Antenna

In this letter, the synthesis of a three-band patch antenna working in E5-L1 Galileo and Wi − Max frequency bands is described. The geometry of the antenna is defined by performing a Koch-like erosion in a classical rectangular patch structure according to a Particle Swarm strategy to optimize the values of the electrical parameters within given specifications. In order to assess the effectiveness of the antenna design, some results from the numerical synthesis procedure are described and a comparison between simulations and experimental measurements is reported. (c) 2007 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works

Design and Analysis of Fractal Monopole Antennas for Multiband Wireless Applications

In this report three antenna designs using fractal geometry have been proposed. Fractal is a concept which is being employed in patch antenna to have better characteristics than conventional microstrip antenna. In the first design, a Sierpinski fractal antenna is proposed for multiband wireless applications. It consists of three-stage Sierpinski fractal geometry as the radiating element. The proposed antenna has compact dimension of 75×89.5×1.5 mm3. The multiband characteristic for a return loss less than 10dB is achieved. The model is applied to predict the behavior of fractal antenna when the height of the antenna is changed. The proposed antenna is considered a good candidate for Multiband Wireless applications. In the second proposal, a Sierpinski Carpet fractal antenna is proposed for multiband wireless applications. It consists of two-stage Sierpinski Carpet fractal geometry as the radiating element. The proposed antenna has compact dimension of 59.06×47.16×1.6 mm3. The multiband characteristic for a return loss less than 10dB is achieved. The major advantage of Sierpinski Carpet antenna is, it exhibits high self-similarity and symmetry. In the third proposal, multiband Koch curve antenna with fractal concept is presented. It consists of two-stage Koch curve as the radiating element. The proposed antenna is a compact dimension of 88×88×1.6 mm3. The multiband characteristic for a return loss less than 10dB is achieved. The proposed design is appropriate for mobile communication systems. CST Microwave Studio Suite 2012 is used to simulate these antennas. All the proposed antennas are fabricated on FR4 substrate of relative permittivity of 4.4 and height 1.6mm has been used

Fractal Array Antennas and Applications

Modern celestial and other advanced wireless communication systems require feasible array antennas with reconfigurable multibeams, broadband, high end of coverage, high gain, less side-lobe level with wider side-lobe level angles, better signal-to-noise ratio and small in size than conventionally achievable. This has initiated array antenna research in different tracks, one of which is by using fractal array antennas. The investigation on fractal-shaped antennas is basically focused on two fundamental areas such as the analysis and design of fractal antenna elements and the application of fractal geometric technology to the design of array antennas. These recursively generated antennas provide new insights into the antenna properties due to their self-similar behaviour. Owing to the feasible geometric construction and advanced properties, fractal antennas find applications in advanced wireless communications, MIMO radars, satellite communications and space observations. This work concentrated here is primarily aimed on the design of fractal array antennas using concentric elliptical ring sub-array fractal geometric design methodology and the reduction of total number of antenna elements at higher expansion factors of both conventional and proposed fractal array antennas

A New Fractal-Based Miniaturized Dual Band Patch Antenna for RF Energy Harvesting

The growth of wireless communications in recent years has made it necessary to develop compact, lightweight multiband antennas. Compact antennas can achieve the same performance as large antennas do with low price and with greater system integration. Dual-frequency microstrip antennas for transmission and reception represent promising approach for doubling the system capacity. In this work, a miniaturized dual band antenna operable at 2.45 and 5.8 GHz is constructed by modifying the standard microstrip patch antenna geometry into a fractal structure. In addition to miniaturization and dual band nature, the proposed antenna also removes unwanted harmonics without the use of additional filter component. Using a finite-element-method-based high frequency structure simulator (HFSS), the antenna is designed and its performance in terms of return loss, impedance matching, radiation pattern, and voltage standing wave ratio (VSWR) is demonstrated. Simulation results are shown to be in close agreement with performance measurements from an actual antenna fabricated on an FR4 substrate. The proposed antenna can be integrated with a rectifier circuit to develop a compact rectenna that can harvest RF energy in both of these frequency bands at a reduction in size of 25.98% relative to a conventional rectangular patch antenna

The resonant behavior of the fibonacci fractal tree antennas

An investigation of a novel fractal tree antenna with the application to two different geometries is presented. The antenna is designed by using the special Fibonacci number sequence which leads to nonuniform branch length ratios to form the fractal tree. This new approach gives better performance, especially in the miniaturization of the antenna, when compared with the conventional designs. The results obtained from the experiments are also compared with the computed ones and there is a very good agreement between the numerical and measured data

A novel design of a fractal antenna for IMT and WiMAX applications

In this paper, a new planar monopole antenna is designed and fabricated for IMT and WiMAX applications. The antenna is based on the use of Sierpinski triangle with a modified ground structure consisting of T-shaped and small rectangular slots printed in the ground. The entire area of the proposed antenna is 55x50mm2 and it is printed on an FR-4 epoxy substrate and fed by a 50 Ohm microstrip line. This new design helps in enhancing both the reflection coefficient and the bandwidth. The electrical performance of the fractal antenna is investigated by the use of CST-MW and HFSS. The simulated results present good performance in terms of matching input impedance and radiation pattern. The electromagnetic results of the fractal antenna are in a good agreement with measurement results

Design and Analysis of Hexagonal Shaped Fractal Antennas

In this report three antenna designs using fractals have been proposed. Fractal is a concept which is being implemented in microstrip antenna to have better characteristics than conventional microstrip antenna. In the first design, a hexagonal shaped monopole fractal antenna for wideband application is designed. The proposed fractal-like geometry is implemented on a microstrip fed planar hexagonal monopole antenna. The iterated hexagonal fractal patch and modified ground plane are employed to achieve the desired wideband characteristics. A notch is also achieved by introducing slits in ground plane. In the second proposal, a new hexagonal shaped patch with modified hexagonal carpet ground plane antenna for multiband application is proposed. Its structure is based on carpet fractal geometry introduced in ground plane. The resonance frequency of a conventional hexagonal patch with full ground is lowered by removing carpet of hexagonal elements from the full ground plane. The antenna is optimized for a dual band operation. The last antenna is the smallest of all the three antennas obtained by taking a hexagonal patch of 8mm side on a fractal ground plane and whole dimension of 30x30mm2. Firstly, full ground plane is taken and studied. Then ground plane is modified by introducing and etching out Symmetrical Vertical Pyramidal Structure (SVPS). All antennas are simulated using CST Microwave Studio Suite 12. For all designs, low cost and readily available FR-4 substrate of relative permittivity of 4.4 and height 1.6mm has been used and fed with 50-ohm microstrip line. All antennas are measured to validate the simulated results. The measured antenna parameters such as return loss, radiation patterns and gain of the proposed antennas are found well matched to the simulated results

Fractals in Antennas and Metamaterials Applications

Recently, telecommunication systems have been requiring more advanced features in the design and operation. Among others a smaller size of devices, which can be integrated for multiple mobile communication systems, applied in one user’s device board, such as PDA or smart phone. Moreover, the cost of mass production should be minimized as much as possible. To meet part of that request, the antennas of these devices should have small size, lower weight, operating in multiple frequency bands and/or be broadband. There are many research methods to achieve this goal, one of which is using the fractal geometries for the shape of antenna elements. In recent years, there are many fractal shapes that have been proposed for such applications, and the designed antennas have significantly improved antenna features such as smaller size, operating in multi-frequency bands, with improved power gain and efficiency. In recent years, the new approach for modern antenna the metamaterials, MTM, is adopted, and sometimes that based on the fractal geometry is adopted

Fibonacci fractal tree antennas

Thesis (Master)--Izmir Institute of Technology, Electronics and Communication Engineering, Izmir, 2004Includes bibliographical references (leaves: 53-55)Text in English; Abstract: Turkish and Englishx, 55 leavesFractal geometry is first defined by Benoit Mandelbrot. A fractal structure is generated with an iterative procedure of a simple initiator by replicating many times at different scales, positions and directions. Fractal structures generated with this method are generally self-similar and the dimensions of these structures cannot be defined with integers. Koch, Minkowski and Sierpinski structures are the most known fractal structures. These structures are commonly used as multiband and wideband antenna designs because of the self-similarity. Furthermore, their special geometry is useful to obtain small antennas which are resonant at lower frequencies. Lowering the resonant frequency has the same effect as miniaturizing the antenna at a fixed resonant frequency. Other important and interesting fractal structures used in antenna designs are the various types of the fractal trees. However, in recent studies the branch length ratios of the fractal tree antennas are taken constant. In this study fractal tree antennas with nonuniform branch length ratios are investigated. By changing the geometry and number of branches of the fractal tree structures the antenna characteristics are examined. The branch lengths and number of branches of the fractal tree antennas are determined by using the Fibonacci sequence. Leonardo Fibonacci (1170 - 1240), a famous Italian mathematician, dealt with geometry and developed a number sequence while observing the nature. Fractal tree antennas are designed with two different geometries in order to improve the resonance behavior of the antennas. The number of branches is decreased, so that less complex fractal tree antennas with the similar performance can be obtained

Sierpinski carpet fractal monopole antenna for ultra-wideband applications

Microstrip antenna is broadly used in the modern communication system due to its significant features such as light weight, inexpensive, low profile, and ease of integration with radio frequency devices. The fractal shape is applied in antenna geometry to obtain the ultra-wideband antennas. In this paper, the sierpinski carpet fractal monopole antenna (SCFMA) is developed for base case, first iteration and second iteration to obtain the wideband based on its space filling and self-similar characteristics. The dimension of the monopole patch size is optimized to minimize the overall dimension of the fractal antenna. Moreover, the optimized planar structure is proposed using the microstrip line feed. The monopole antenna is mounted on the FR4 substrate with the thickness of 1.6 mm with loss tangent of 0.02 and relative permittivity of 4.4. The performance of this SCFMA is analyzed in terms of area, bandwidth, return loss, voltage standing wave ratio, radiation pattern and gain. The proposed fractal antenna achieves three different bandwidth ranges such as 2.6-4.0 GHz, 2.5-4.3 GHz and 2.4-4.4 GHz for base case, first and second iteration respectively. The proposed SCFMA is compared with existing fractal antennas to prove the efficiency of the SCFMA design. The area of the SCFMA is 25×20 mm2, which is less when compared to the existing fractal antennas