Fractal Ring Research Articles

Fractal Ring Shaped with Saw Feed Microstrip Patch Antenna for Wireless Utilizations

Fractal Ring Shaped with Saw Feed Microstrip Patch Antenna for Wireless Utilizations

Triple band terahertz absorption based fractal ring shaped ultrathin mustard oil adulteration sensor

A tri-band terahertz (THz) absorber for sensing the adulteration percentage in mustard oil is proposed in this paper. It consists of a gold based metallic resonating geometry and metallic ground plane on the top and bottom layers of the dielectric material respectively. It has three absorption peaks with peak absorptivity of 99.74%, 99.96% & 99.94% and Full Width at Half Maxima (FWHM) of 0.57, 0.862 & 1.112 THz at 4.6296, 8.295 & 12.6309 THz respectively. The proposed absorber’s unit cell volume has an overall volume of 10 μm×10μm×1.61μm (0.15432λL×0.15432λL×0.024846λL where λL is wavelength at lowest operating frequency i.e. 4.6296 THz). It has polarization insensitive absorption performance under normal incidence and incident angle (θ∘) stability up to 50° for A≥90%. The proposed structure is simulated through by using CST & HFSS. The results are validated by developing an equivalent circuit model (ECM). The results of CST, HFSS and ECM are found to be in good agreement. A sensitivity varying from ∼0.23 THz/RIU to ∼1.62 THz/RIU is achieved for Refractive Index (RI) sensing case, whereas a high sensitivity in the range of ∼0.4 THz/RIU to ∼2 THz/RIU is achieved for mustard oil adulteration sensing case by mounting the absorber’s top surface with a polyimide based container filled with an analyte (either refractive index material or mustard oil). During the validation, a maximum ∼0.16% error in mustard oil adulteration estimation is achieved. The proposed sensor has advantages of simple & ultra compact dimensions, high sensitivity and minimal error in impurity concentration estimation with respect to other absorber-based sensors.

A novel circular fractal ring UWB monopole antenna with dual band‐notched characteristics

AbstractThis paper presents a novel circular fractal ring monopole antenna for ultra‐wideband (UWB) hardware with dual band‐notched properties. The proposed antenna consists of four crescent‐shaped nested rings, a tapered feeding line at the front of the dielectric material, and a semicircular ground plane on the backside. In this design, the nested rings are used both as a radiation element and a band rejection element. The proposed antenna has a bandwidth of 9.03 GHz, which works efficiently in the range of 2.63 GHz–11.66 GHz with the dual notched bands of Worldwide Interoperability for Microwave Access (WiMAX) at 3.15 GHz–3.66 GHz and wireless local area network (WLAN) at 4.9 GHz–5.9 GHz, respectively. The antenna has a compact size of 20 mm × 30 mm × 1 mm (0.177 × 0.265 × 0.0084 λ0) and is implemented using a flame‐retardant type 4 (FR4) material. It has a maximum gain of approximately 4 dB in its operating range, and experimental results support the simulation predictions with high accuracy. The findings of this study imply that the designed antenna can be utilized in UWB applications.

Random Knotting in Fractal Ring Polymers.

Many ring polymer systems of physical and biological interest exhibit both pronounced topological effects and nontrivial self-similarity, but the relationship between these two phenomena has not yet been clearly established. Here, we use theory and simulation to formulate such a connection by studying a fundamental topological property—the random knotting probability—for ring polymers with varying fractal dimension, df. Using straightforward scaling arguments, we generalize a classic mathematical result, showing that the probability of a trivial knot decays exponentially with chain size, N, for all fractal dimensions: P0(N) ∝ exp(−N/N0). However, no such simple considerations can account for the dependence of the knotting length, N0, on df, necessitating a more involved analytical calculation. This analysis reveals a complicated double-exponential dependence, which is well supported by numerical data. By contrast, functional forms typical of simple scaling theories fail to adequately describe the observations. These findings are equally valid for two-dimensional ring polymer systems, where “knotting” is defined as the intersection of any two segments.

A Wideband Hybrid Fractal Ring Antenna for WLAN Applications

We propose the design of a novel fractal antenna that is both unique and performance-driven. Two important antenna design features, miniaturization and wideband operation, are combined in this work. A ring-shaped antenna is designed using the well-known fractal geometry. This hybrid geometry is a fusion of meander and Koch curve shapes. The geometrical construction of the proposed antenna is compared to the standard Koch curve geometry. It is shown that combining the meander and Koch curve shapes increases the effective electrical length. The wider bandwidth is achieved by bringing the higher modes together. The overall dimensions of proposed meander Koch curve fractal ring antenna are 45 × 25 × 1.6 mm3. The resonance frequency of the antenna is between 4.94 and 6.12 GHz (% BW = 21.83), which covers the entire 5 GHz WLAN band. The prototype has been fabricated and experimentally verified.

Compact Circular CSRR Loaded Koch Fractal Inspired Frequency Band Reconfigurable Antenna

A compact frequency band reconfigurable dual-mode antenna utilizing both Koch fractal geometry and circular complementary split ring resonators (CSRRs) is presented in this paper. The proposed antenna can be electrically switched into both dual- and single-band resonance modes. A Koch curve derivative novel fractal curve is used to design the patch boundary of the antenna. Two optimized circular CSRRs are loaded inside the antenna geometry to achieve double-band resonance. The antenna operates at both 5.1[Formula: see text]GHz (upper WLAN band) and 9.6[Formula: see text]GHz ([Formula: see text]-band) in dual resonance mode and resonates only at 8[Formula: see text]GHz ([Formula: see text]-band) in single resonance mode. A properly biased RF-range PIN diode placed at the slotted ground plane reconfigures the antenna in two operating modes by switching into its ON–OFF states. The antenna is fabricated on cost-efficient epoxy (FR-4) substrate consuming the maximum dimension of [Formula: see text] which is much more compact than the conventional rectangular patch antennas designed for similar bands. Stable radiation characteristics with reduced cross-polarization are achieved at all the resonant bands of the antenna. A prototype of the proposed antenna is fabricated and measured. The simulated results are in good agreement with the measured ones.

High Directivity Broadband Hexagonal Fractal Ring Antenna with Modified Ground

A highly directive fractal antenna with a novel shape is proposed in this paper. Finite Element Method based simulations were carried out on the first three iterations of a hexagonal fractal ring and the performance was measured in terms of the resonant behavior, directivity, radiation efficiency, current distribution, and radiation pattern. The second iteration fractal antenna radiates well along the broadside direction at the fundamental mode of operation. The ground plane was modified to improve the performance further. The antenna, etched on an FR4 substrate, has a directivity of 11.8 dB along the broadside direction with multi-frequency broadband performance over the frequency range of 3.12-7.46 GHz. Therefore, the proposed fractal antenna can be used for Wireless LAN applications. The antenna was fabricated and measured in order to validate the results.

A Novel Printed Antenna Based on Fractal Ring for UWB Application

In this paper, a novel printed antenna based on fractal ring for UWB (ultra-wideband) application was mentioned. It was mainly composed of three main rings, each of the two main rings was connected by a number of small rings.The proposed antenna was printed on FR4 media substrate, which with the dielectric constant of 4.4 and loss tangent of 0.02.The maximum dimension of antenna was 38mm×28mm×1.6mm. Impedance bandwidth of VSWR < 2 was 2.1-13.7 GHz, it covers UWB spectrum (3.1-10.6 GHz) specified by FCC (Federal Communications Commission). There were many advantages such as good radiation characteristics and compact structure, it's suitable for wireless communication systems in S-band, C-band, X-band, UWB band and so on.

A Novel Printed Antenna Based on Fractal Ring for UWB Application

A Novel Printed Antenna Based on Fractal Ring for UWB Application

Triband Operation Enhancement Based on Multimode Analytics of Modified Rhombic Ring Structure with Fractal Ring Parasitic

This paper presents a triband operation enhancement based on multimode analytics of a monopole antenna designed by combining a rhombic ring radiator with a strip on a top layer and a fractal ring resonator placed at the bottom layer. The proposed antenna can achieve triband operation to support the modern wireless communication systems. The antenna size is approximately 36 × 52 mm2, which is quite compacted compared with the revised antenna. The simulation and measurement results are in good agreement. The antenna covers the operating bands at 22.22%, 9.8%, and 31.27% at the resonant frequencies of 1.8 GHz, 2.45 GHz, and 3.71 GHz, respectively, to support the application bands of LTE 1800, WLAN IEEE802.11b/g, WiMAX, and IMT Advanced Systems (5G). The average gain of the antenna is about 2 dBi. Also, the radiation patterns are omnidirectional for all operating frequencies.

Design of a Polarization-Independent Dual-Band Electromagnetically Induced Transparency-Like Metamaterial

In this study, the classical analog of single and dual-band electromagnetically induced transparency is demonstrated with a four-fold symmetric metamaterial consisting of a Minkowski fractal ring resonator surrounded by a square ring resonator. The proposed metamaterials show high transmission ratios at the polarization independent resonances, as confirmed by the applied two different numerical methods. Delay-bandwidth products are found to be 0.34 and 0.61 at the resonances of the dual-band metamaterial. The peak frequencies and transmission ratios maintain also for oblique angle of incidences. These features of the proposed metamaterials are promising for single and multi-band filtering applications as well as for slow light and sensing devices.

Compact dual‐band fractal hexagonal ring monopole antenna for RFID and GSM applications

AbstractA novel compact dual‐band fractal antenna suitable for radio frequency identification (RFID) and GSM 1800 applications is developed and presented in this paper. This is achieved by adequate combination of three slotted hexagonal fractal rings which resulted in a significantly reduced size structure that can operate in the frequency ranges [0.895‐0.962 GHz] and [1.706‐1.856 GHz] that cover the frequency bands allocated to the intended applications. The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.

A Compact Dual-Band Planar Monopole Antenna Using Fractal Rings and A Y-Shaped Feeding Transmission Line

Abstract This paper presents a novel design approach of a compact dual-band monopole antenna with an overall size of 18.9x13x1.6mm3. The proposed antenna is composed of a fractal ring shaped patch fed by a Y-shaped transmission line on the top side of the substrate and a second fractal ring along with a U-shaped ground plane on the bottom side. The second fractal ring, identical to the radiating ring, is loaded and a rectangular slot is etched at the top side of the ground plane respectively, to achieve dual-band characteristic and improve the impedance matching. The effect of standard ground-plane (SGP) of a laptop computer is incorporated in the design; the antenna is mounted on a SGP in order to investigate its performance. The antenna covers widely the frequency bands of the WLAN 2.4 GHz (2.2–2.52 GHz) and WiMAX 3.5 GHz (3.32–4.35 GHz), and exhibits an omnidirectional radiation pattern in the H-plane and a monopole like radiation pattern in the E-plane. A good agreement between the simulated and measured results indicates that the proposed dual-band antenna design is suitable for WLAN/WiMAX applications.

A New Design of UHF RFID Tag Antenna Using Double Negative Metamaterial Based on Fractal SRR

In this paper, a new design of miniaturized passive UHF RFID tag antenna using double negative metamaterial based on fractal split ring resonator is proposed. This tag antenna is designed on paper substrate having dielectric constant of 3.3, tangent loss of 0.04 and height of 250 micrometers. The effective read range can be obtained when the input impedance of the antenna is conjugate match with the complex impedance of the RFID chip. The dimensions of the metamaterial tag antenna are optimized and simulated by using the electromagnetic solver Momentum integrated in ADS. The obtained result was validated by CST Microwave Studio. The proposed tag antenna is designed to cover the North and South American UHF RFID band (902-928MHz). The input impedance bandwidth of the proposed tag antenna is 28 MHz (from 902MHz to 928MHz), the reflection coefficient is about -35dB and the simulated gain is about 1.73dB.

Fractal planetary rings: Energy inequalities and random field model

This study is motivated by a recent observation, based on photographs from the Cassini mission, that Saturn’s rings have a fractal structure in radial direction. Accordingly, two questions are considered: (1) What Newtonian mechanics argument in support of such a fractal structure of planetary rings is possible? (2) What kinematics model of such fractal rings can be formulated? Both challenges are based on taking planetary rings’ spatial structure as being statistically stationary in time and statistically isotropic in space, but statistically nonstationary in space. An answer to the first challenge is given through an energy analysis of circular rings having a self-generated, noninteger-dimensional mass distribution [V. E. Tarasov, Int. J. Mod Phys. B 19, 4103 (2005)]. The second issue is approached by taking the random field of angular velocity vector of a rotating particle of the ring as a random section of a special vector bundle. Using the theory of group representations, we prove that such a field is completely determined by a sequence of continuous positive-definite matrix-valued functions defined on the Cartesian square [Formula: see text] of the radial cross-section [Formula: see text] of the rings, where [Formula: see text] is a fat fractal.

Fractal: An advanced multidimensional range query lookup protocol on nested rings for distributed systems

One of the key issues in large-scale distributed systems such as P2P and grids is the capability of efficient multidimensional range query processing. Although several methods have recently been proposed for solving this problem on distributed systems, these methods have not been able to meet the fundamental necessity of a typical method on large-scale distributed systems, i.e., scalability.This paper presents Fractal, a fully decentralized and highly scalable multidimensional range query lookup protocol for distributed systems. In this work, to organize the available nodes in the system, an n-dimensional space called Key Space is utilized. The available nodes on the nested Fractal rings maintain information about only O(logN) other nodes, and the Fractal lookup protocol discovers the destination node through these nested rings with a logarithmic cost. Because of its flexibility, Fractal allows the system to create a concept called Layering, which minimizes the probability of the wide-area message transfers (WAMTs) during the lookup process. Using several criteria, Fractal is compared with several successful methods that have recently been presented. Simulation results show the efficiency and performance of Fractal in networks of different sizes.

Highly compact UWB bandpass filter based on composite right/left-handed transmission line and meander fractal like ring slot in ground

An ultra-wideband (UWB) highly compact bandpass filter with extremely high passband bandwidth is presented. The proposed structure is made using three-staged stepped-impedance lines and a composite right/left-handed transmission line (CRLH-TL) synthesized with meander fractal like ring slot in the ground and series capacitive gap in conductor strip. The capacitive gap in conductor strip and meander fractal like ring slot in the ground plane play major role for controlling the lower and higher cut-off frequencies. The equivalent circuit model of proposed filter is demonstrated and lumped parameters are extracted. A prototype is fabricated to experimentally validate the performance of proposed filter. The proposed UWB filter has extremely wide −10 dB return loss passband bandwidth from 3.14 to 18.26 GHz with relative bandwidth of 142% and insertion loss better than 0.5 dB. Also it achieves a wide upper-stopband from 19.7 to 24.4 GHz with insertion loss better than 13.0 dB, return loss &lt;1.5 dB and sharpened rejection skirts outside the passband at both lower and upper frequency ends. Good agreement is found between simulated and measured results with measured group delay variation in the passband &lt;0.65 ns.

Investigation and design of an ultra-wideband fractal ring antenna for notch applications

In this article, an ultra wideband ring antenna with a fractal formation for notch application is presented. The antenna was printed on FR-4 substrate, which was a low cost one with the relative permittivity of 4.4 and thickness of 1.6 mm. The total dimension of antenna was 50 mm × 50 mm. It could be applied as a notch antenna for propagation rejection in IEEE 802.11a for instance by covering were as without conflicting with wireless systems. The prototype antenna presented in this article, has a rejection band at 5–6 GHz and covers the frequency range of 2.1–11 GHz with the VSWR of less than 2. For improvement of the notch frequencies and for obtaining dual notch band characteristic some changes in prototype antenna with a slot at fractal structure have been performed. The final antenna had dual notch band at 2.5 and 5.5 GHz. The current distribution in the notch frequency has been provided. The efficiency has also been checked for the entire frequency band. The maximum antenna gain was achieved between 2–8 dBi. All the simulations were done in HFSS and compared with the experimental results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1629–1634, 2016

Semi fractal three leaf clover-shaped CPW antenna for triple band operation

This article presents a unique and compact coplanar waveguide CPW antenna that exhibits triband operation with circular polarization. The single antenna was designed to operate simultaneously in the following bands: WiMAX 3.3-3.6 GHz, wireless local area network WLAN 5.15-5.825 GHz, ITS 5.795-6.400 GHz, and ITU-R 7.725-8.5 GHz. The realization of the triband antenna was achieved by using two semi fractal ring patches resembling the shape of a three leaf clover, and by introducing a pair of symmetrical L-shaped slits in its ground plane. The antenna's physical parameters were investigated to fully understand their affect on the antenna's performance. The salient parameters obtained from this analysis enabled the optimization of the antenna's overall characteristics. The design concept was confirmed by fabricating the antenna prototype and measuring its characteristics. The proposed antenna has dimensions of 20 × 20 × 1 mm3. Measured results show the antenna exhibits circular polarization in WiMAX and ITU-R bands, and linear polarization in the WLAN band. The antenna radiates omnidirectionally in the H-plane, and approximately bidirectionally in the E-plane. In addition, the antenna presents stable gain over the triband. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:413-418, 2015.

Unified Login Authentication Method Based on Cloud Computing

According to the single sign-on authentication mode, cloud computing unified login authentication method was put forward, and point set topology changing method was used for generating fractal random key, improved login authentication safety grade. Firstly, analyzed cloud computing login authentication system structure, and then used network public databases of fingerprint image as an example do fractal changes ring operation, generated a pseudo-random sequence, then the sequence encrypted and sent to the server for authentication through UDP. Lastly, made a simulation example.