Fractal Antenna Research Articles

Triple Frequency CPW Fed Fractal Antenna for Wireless Applications

A Triple Frequency CPW feed fractal patch antenna has been designed for the S and C band applications with the operating frequencies of 2.29GHz, 3.46GHz and 5.89GHz. Patch has been etched with slots in a periodic manner which led for the generation of triple band of resonance. Flame Retardant Glass epoxy is taken as substrate material which is having a thickness of 1.6mm and a 50Ω stripline has been used to excite the antenna. Fractal technique has been implemented to attain the triple frequency of operation. The overall dimension of the antenna is 60mm×60mm×1.6mm. The Proposed antenna is having resonance which is covering the S and C band frequencies with a return loss value less than -10dB for entire bandwidth. Commercially available 3D simulator Ansys HFSS software has been used to design the proposed antenna.

Fabrication of Hybrid Fractal Microstrip Antenna for Mobile and Wi-Max Applications

This paper presents the fabrication of an octagonal fractal hybrid micro strip radiator patch antenna that operates over a frequency range of 1.5 GHz to 2GHz suitable for low frequency wireless and mobile applications. The radiator has a dimension of 85x85mm2on the radiating side and 100x86mm2 ground plane. The model is fabricated on Fire Redundant4 substrate with thickness of 1.6mm over a 10x10mm2dimension and uses coaxial feeding technique. The model is tested for its performance in the range of 1.5 to 2 GHz on the radiator test bench consists of MIC10 antenna trainer kit with an allowable frequency of up to 2GHz. The radiation characteristics shown are having good return loss and average gain of 39dB with omni directional radiation pattern. The size is to be optimized as the dimensions are very large compared to the usual requirements.

Dual Band Minkowski Fractal Antenna for Maritime Radio Navigation Services

A dual band low profile fractal antenna is proposed for Maritime Radio Navigation Services (MRNS). Minkowski fractal geometry is used on both the vertical boundaries of basic patch structure and by adjusting the fractal dimension desired operating frequency is achieved. The effect of antenna dimensions on the bandwidth is determined through the parametric analysis. Proposed antenna operates at 3 GHz and 9.4 GHz with a gain of 6.3 dB and 2.5 dB respectively. Furthermore, the resonating and radiation properties of the proposed antenna are measured experimentally. Measured results of the proposed antenna are highly convincing and in good agreement with simulated results.

Carving Plasmon Modes in Silver Sierpiński Fractals

The surface plasmon resonance (SPR) modes of the first three generations of a Sierpinski fractal triangle are investigated using electron energy loss spectroscopy (EELS) complemented with finite difference time domain simulations. The Sierpinski fractal geometry is created in a subtractive manner, by carving triangular apertures into the triangular prism of the previous fractal generation. The ability of the fractal antenna to efficiently utilize space in coupling to long wavelength excitations is confirmed on the single nanostructure level via redshifting of the primary dipole mode as the fractal generation is increased. Through application of the Babinet principle, it is demonstrated that this spectral shift is caused by coupling of two degenerate orthogonal dipolar modes of a single triangle with two degenerate orthogonal dipole modes of the triangular aperture occupying the center of the first generation fractal. It is also shown that the spectral position and strength of the dipole mode can be tuned ...

Microstrip Hexagonal Fractal Antenna for Military Applications

Abstract Novel and miniaturized hexagonal Microstrip patch antenna design is presented in this paper. Patch is fractured using Sierpinski and Koch structures to make the antenna applicable for multiband applications. Additionally ground is defected to enhance the bandwidth and further size is reduced. Material FR-4 (εr = 4.4)has been chosen to design proposed antenna and substrate thickness as 1.59 mm. Microstrip feed technique is used as it provides better results. Gain obtained in this case is 5.57 dB, 7.49 dB and 4.02 dB with bandwidth as 606.8 MHz, 507 MHz and 2 GHz at 8.3 GHz, 12.6 GHz and 17.6 GHz resonant frequencies. The antenna is better to other designs in terms of parameters like bandwidth, directivity, polarization, gain, return loss and dimension. The antenna provides application for military appliances. A good concord is obtained in Simulated and measured results.

Compact asymmetric fractal frequency and pattern reconfigurable monopole antenna

A compact frequency and pattern reconfigurable monopole for LTE and WLAN applications is presented. The antenna consists of an asymmetric fractal patch which is derived from a bow-tie antenna and optimized using Pattern search algorithm. The antenna operates at 1.8 GHz and 5.2 GHz frequency with a different radiation pattern for each case. A single PIN diode is used to achieve frequency and pattern reconfigurability. The antenna is simulated using Ansoft High Frequency Structural Simulator (HFSS) software and fabricated on FR4 substrate with the relative permittivity of 4.4; having size of 30 mm * 24 mm and thickness of 1.6 mm.

A Modified Two-Step ANN Ensemble Approach to Improve Generalization and its Application in Fractal Antenna Design

In this work, a fractal antenna with rectangular base shape has been designed for 5.2[Formula: see text]GHz resonant frequency. Recently, ANN modeling of fractal antenna parameters have shown to be an effective approach for its design optimization. But the selection of ANN ensemble members and their output aggregation are two important issues for efficient operation of ANN ensembles. A novel two-step method based on output sensitivity of ANN and genetic algorithm optimization of ensemble members has been proposed in this paper for addressing the above two issues. The proposed approach, which is a modified form of existing technique, has been first validated by applying it over six benchmark functions and compared with existing approach for improved performance. Further, the proposed approach has been used to develop an ANN ensemble for design optimization of fractal antenna at 5.2[Formula: see text]GHz resonant frequency. The selected antenna geometry has been experimentally verified and has shown significant miniaturization of 48.34% as compared to conventional rectangular micro-strip antenna.

A Compact Plus Shaped Carpet Fractal Antenna with an I-Shaped DGS for C-band/X-band/UWB/WIBAN applications

This article presents the design and development of a compact broadband “+” shaped aperture coupled carpet fractal antenna with a defected ground structure (I shaped slot in the ground) for broadband/ultra wideband (UWB) and a multiband characteristics. The antenna has overall dimensions of 8.4 cm × 5.5 cm × 3.2 mm and is fed using aperture coupled feeding mechanism. It shows an impedance bandwidth (< 10 dB) of 4460 MHz from 6.93 to 11.39 GHz with fractional bandwidth of 0.48 at the center resonant frequency of 9.16 GHz. A multiband behavior is also exhibited by this antenna from 3.9–4.08 GHz, 4.8–5.06 GHz and 6.1–6.4 GHz with impedance bandwidths of 180 MHz, 260 MHz and 300 MHz respectively. It therefore supports the wireless applications of Wi-MAX (3.8–4.1 GHz), Wi-BAN/long distance radio telecommunication (4.8–5.06 GHz), wireless sensor networks (6.1–6.4 GHz), satellite (7.4–7.8 GHz) and UWB (6.9–11.03 GHz). The antenna is designed as a ‘+’ shaped patch with fractal rectangular slots cut out from it up to iterations of second order that allow the antenna to support multiband characteristics. The bandwidth at these bands is improved by using I shaped defected ground structure (DGS) and a parasitic feeding method i.e. aperture coupled feeding (Karur et al., in: ICMARS (IEEE), Jodhpur, India, pp. 266–270, 2014).The antenna has a compact structure with two layers of FR4 substrate, the ‘+’ shaped carpet fractal printed on the upper substrate layer and the lower substrate has a ground layer printed on its top and feed line on its bottom layer respectively. It shows a simulated peak gain of 4 dB at an operation frequency of 7.95 GHz. The antenna design and simulations are done using CST MWS V14. The Simulation results in terms of impedance bandwidth, smith chart, gain are presented in this article. To validate the impedance bandwidth results, the proposed carpet fractal antenna is experimentally tested using a vector network analyzer and the measured results are found to be closely matching with the simulated ones, allowing the antenna to be practically suitable for the afore mentioned wireless applications.

On the Design of 2×2 MIMO Fractal Antenna Array for C band applications

A 2×2 MIMO planar fractal antenna array using Sierpinski gasket along with microstrip feed line has been investigated. Different configurations of antenna array has been studied. The optimized unit element used in array is further modified geometrically by corner rounding and cut in feed to improve its performance including gain. Proposed fractal array antenna resonates at 4.19 GHz and 7.86 GHz lies in C band and simulated using High frequency structure simulator. Such an attempt has been rarely reported in the literature. Simulated reflection coefficient shows that Proposed antenna works in C band frequency range for various applications and results are quite promising

A Compact Ultra-Wide Band Rhombus Shaped Fractal Antenna With Metamaterial In the Ground Plane

An ultra wide band pattern antenna with rhombus fractal geometry has been proposed in this paper. In order to enhance the gain and directivity of the antenna, Meta material iss placed in the ground plane. The effect of the meta material on the overall performance of the rhombic patch is also presented in this paper. The design and analysis of the proposed fractal antenna is carried by using CST Microwave Studio 2015 and MATLAB R2014b. The measured antenna characteristics such as gain and directivity of the proposed antennas are found well matched to the simulated results.

English

English

Design of a Koch Shaped Fractal Antenna for Wireless Applications

Design of a Koch Shaped Fractal Antenna for Wireless Applications

Design of Hybrid Fractal Boundary Antenna for RF Energy Harvesting Applications

The fractal antennas have multiband behavior and also have the capabilities of the size reduction as compared to the other patch antennas. Ahybrid fractal boundary antenna has been designed and simulated in this paper for radio frequency energy harvesting (RFEH). The designed antenna has the multiband behavior, as it resonates at the two frequencies. The multiband behavior of the antenna helps in harvesting the energy from various frequencies band and improves the output of the circuit. This hybrid fractal boundary antenna uses the microstrip feed line to improve the matching performance of the antenna.

Investigation on novel wideband fractal antenna design based on cylindrical shape dielectric resonator

This article explains a novel approach for achieving wideband characteristics in case of dielectric resonator antenna (DRA). Wideband characteristic has been realized by uniting the concept of vastu purusha mandala (VPM)-based fractal geometry with dielectric resonator antenna. VPM is Hindu religion-based fractal geometry, which provides the advantage of decrease in volume to surface area of the radiator. This concept is useful to enhance impedance bandwidth of proposed antenna. For the purpose of validation, prototype of proposed antenna design has been fabricated as well as tested. After experimental testing, it is confirmed that the proposed radiator functions over the frequency range 2.6-4.34 GHz with a percentage bandwidth of 46.52%. The proposed radiating arrangement provides peak gain of 6.3 dBi and stable far-field characteristics. All these features make it applicable for WiMAX application (3.3 GHz).

Defected Ground Based Fractal Antenna for S and C Band Applications

Defected ground based modified rectangular fractal patch antenna for mobile devices communication in Delay Tolerant Networks, Wireless sensor networks and Mobile Adhoc networks is being presented in this paper. In view of the overwhelming demand of small and light weight micro-chip patch antenna in wireless communication in the recent years the size of antenna has been reduced considerably. Wideband behaviour of antenna is achieved with improved values of performance parameters like gain, reflection coefficient (S11), Voltage Standing Wave Ratio (VSWR), radiation pattern and bandwidth. The proposed antenna covers various frequency bands like earth to space communication (2.17–2.2 GHz), satellite communication (2.3 GHz), wireless local area networks (2.4–2.484 GHz), Wi Fi (2.4 GHz for 802.11b and 802.11g), Radio Frequency Identification, Microwave oven, Bluetooth (2.45 GHz), Wireless Computer Networking (2.4 GHz), Mobile Wi-Max (2.5–2.69 GHz), Direct to home services (2.5–2.7 GHz), Wi-Max (3.3–3.6) Satellite Communication for Downlink (3.7–4.2 GHz) at various resonating frequencies. High Frequency Structural Simulator; v13 has been used to simulate the proposed antenna. The antenna has been designed and simulated using FR4 epoxy substrate with relative permittivity 4.4 and having size of 32 mm × 30 mm × 1.6 mm with line feeding technique. Ground plane has also made defective. The antenna shows the bandwidth of 2830 MHz with gain of 6.83 dB, reflection coefficient (S11) − 19.72 dB and VSWR of 1.23 at resonant frequency 2.85 GHz. Size of the antenna stands reduced by 38.73% with deflective ground surface and frequency shifted towards the lower side. The antenna operates from 2.05 to 4.88 GHz covering S and C band applications.

Frequency tuned Minkowski island fractals RHCP antenna optimised for three‐band GPS receiver

This study presents an antenna design that operates at the three bands of the Global Positioning System (GPS) receiver. The optimised Minkowski island fractal structure combined with the central window is used to design the radiation surface to reduce the size and adjust the resonance frequencies of the antenna. The antenna was designed, and simulated by HFSS computer code, and was fabricated on microwave laminate FR4-epoxy by fast laser prototyping. The resulting fractal antenna has been operating at three GPS-bands: f L2 = 1.227, f L5 = 1.176, and f L1 = 1.575 GHz, with return loss S 11 21.5 MHz, for VSWR < 2, at 50-Ω input impedance, the power gains ∼2.4, 2.85, and 4.2 dBi, and axial ratio of right-handed circular polarisation 1.5, 03, and 06 dB at f L5, f L2, and f L1, respectively. The simulated and experimental results agree favourable.

Four element ultra‐wideband fractal multiple‐input multiple‐output antenna

AbstractA four elements fractal antenna for UWB multiple‐input multiple‐output (MIMO) applications is presented. Each element comprises three iterations of inner tapered rectangular radiator and rectangular notch loaded coplanar waveguide rectangular ground planes. A rotated “+”shaped rectangular strip pair is introduced to enhance the isolation between two diagonally opposite elements. This antenna is operating over a frequency spectrum of 4.8‐19.4 with an intra‐element isolation of more than 15 dB. In addition to good radiation characteristics, desirable values of diversity performance parameters are achieved.

A novel reconfigurable microstrip fractal UWB antenna with six variable rejection frequency bands

AbstractIn this paper, a new reconfigurable microstrip fractal ultra-wideband antenna with a capability of variable rejection frequency bands is presented. The main patch of this antenna has two modified C-shaped gaps. Also, on these c-shaped gaps, 10 ideal MEMS switches are used to produce band-notch frequencies at six different frequencies of: 5.4 GHz (5.2–5.5), 5.8 GHz (5.7–5.9), 6.1 GHz (5.9–6.3), 7 GHz (6.9–7.2), 7.9 GHz (7.7–8.1), and 8.4 GHz (8.2–8.6). This antenna is fed by a 50 Ω microstrip line and works in a wide bandwidth of 2.9–11 GHz. The antenna is designed and fabricated on an inexpensive substrate of FR4. Dimensions of the antenna are 31.2 × 38.4 mm. Measurement and simulation results are in good agreement.

Spider-shaped fractal MIMO antenna for WLAN/WiMAX/Wi-Fi/Bluetooth/C-band applications

A spider-shaped fractal MIMO antenna is proposed for wireless local area network (WLAN), worldwide interoperability for microwave access (WiMAX), wireless fidelity (Wi-Fi), Bluetooth and C-band applications simultaneously. It comprises two microstrip line fed fourth iterative antenna elements and two Y-shaped back plane structures connected to common partial rectangular ground plane. It covers four distinct frequency bands 2.24–2.50 GHz, 3.60–3.99 GHz, 4.40–4.60 GHz, and 5.71–5.90 GHz. The proposed antenna resonates at 2.43/3.83/4.4/5.8 GHz. The arms of spider-shaped structure result in multiband operation. The multiple arms of spider-shaped fractal MIMO antenna provide low correlation between radiators. Due to the spider shaped radiator, an inter-port isolation of more than 10 dB is achieved with DGS. This antenna has a gain of more than 2.0 dBi in each band and an envelope correlation coefficient of more than 0.08 across the entire frequency spectrum.

Design methodology of the fractal annular ring antennas with the wideband operation

In this paper, a novel annular ring antenna is proposed to achieve a multi-wideband antenna. The structure is annular ring. For systematic design of the antenna, fractal shape is employed. Each iteration of the structure acts as a matching load for the previous section. Consequently, by increasing the electrical current path, multi-band and wideband performances can be achieved. For tuning the frequency bands, three slots are cut from the ground plane. The first operating band is from 1.47 GHz to 1.86 GHz (fractional band width (FBW): 23.42%), the second band is from 2.44 GHz to 3.51 GHz (FBW: 35.96%), and the third one is from 4.49 GHz to 5.34 GHz (FBW: 17.29%). Furthermore, the antenna has the ability to cover the ultra-wideband (UWB) spectrum by inserting two vias in the substrate. Using vias, impedance matching of the antenna is improved in the frequency range from 2.8 GHz to 5 GHz (FBW: 56.4%) with criteria |S11|<−10 dB. Also, it has a noticeable impedance bandwidth (FBW: 117%) from 1.3 GHz to 5 GHz with criteria |S11|<−6 dB. A prototype of the proposed antenna is fabricated and tested. The measurement and simulation results are in good agreement.