Fractal Patch Research Articles

Genetic Algorithm-Based Optimization of a Miniature Wearable Fractal Patch Antenna for Medical Purposes

Genetic Algorithm-Based Optimization of a Miniature Wearable Fractal Patch Antenna for Medical Purposes

A METAMATERIAL SLOTTED PATCH ANTENNA WITH METASURFACE

In this project, a novel, compact, high-gain, directive, and superstrate configuration-based metasurface (MS) antenna has been designed, which incorporates a fractal-shaped slotted patch having a periodic arrangement of square patches along with a shorting via at its center and a couple of rectangular slots in the ground plane. The MS is designed over the FR4 dielectric by introducing a periodic arrangement of unit cells in which the unit cell is structured by a S-type patterned patches. The MS is separated by a layer from the conventional patch antenna designed over the FR4 dielectric, thereby acting as a superstrate. The proposed antenna provides good impedance matching across the frequency region of 10.14–10.94 GHz with a unidirectional radiation pattern. A maximum return loss of -18.4dB have been realized at 10.2GHz. As the proposed antenna is more efficient, it can be promoted for X-band operations, such as satellite communication, defense purpose, and medical supervision. Keywords— Metasurface (MS), microstrip, slotted fractal patch, superstrate.

Optimisation of asymmetries in mm-wave single-element fractal antenna for gain-bandwidth enhancement

ABSTRACT In this study, a low-loss substrate was used to create an Asymmetric Irregular Hexagonal Fractal (AIHF) mm-wave antenna. The antenna consists of an Asymmetric Defected Ground Structure (ADGS) attached to the bottom of a 0.55λ0 ×0.40λ0 ×0.032λ0 mm3 substrate and an Irregular Hexagonal Fractal (IHF) patch on top of the substrate. The proposed fractal technique is unique and based on fractal-slot 3-stage iterations. The IHF patch is created by etching seven fractals arranged symmetrically about the y-axis, one of which has a central 1/3rd (scaling) iteration factor and six hexagonal fractals that are 1/9th of the parent 0th order iteration. On the patch, these fractal slots are evenly spaced out. By etching an Asymmetric Cascaded Double Dumbbell (ACDD) slot on the ground plane, an ADGS is created. With this etching in the patch and ground, a gain of > 5.0 dBi for a −10 dB S11 bandwidth of 4.655 GHz (32.84–37.215 GHz), a recorded peak gain of 13.4 dBi is at 33.55 GHz and an average radiation efficiency of 87.75% is achieved. Using the High-Frequency Structure Simulator (HFSS), the width of ADGS, the position of ACDD on ADGS, and the dimensions of etched fractals are optimised through a pattern search parametric iterative technique. These results are validated using the Vector Network Analyser (VNA), and the Anechoic Chamber and it is revealed that they agree well with the simulated results. The designed AIHF antenna’s RLC electrical equivalent circuit modelling is presented along with evaluated R, L, and C values.

Modified pentagonal fractal antenna for ultra-wideband applications in communication systems

ABSTRACT Due to the recent expansion in the generations of the communications systems, it is utmost priority to transmit a large amount of data over a wideband frequency spectrum. For this single ultra-wideband (UWB) antennas are the prime choice as compared to the multiple narrow band antennas. A modified pentagonal fractal patch antenna with a modified ground plane covering ultra-wideband has been proposed. The antenna has a compact size of 25 mm × 25 mm × 1.6 mm with peak gain of 2.2 dB. The UWB coverage of the design is achieved by implementing modified co-planar ground, modified fractal geometry and coplanar feed. The proposed design possesses the significant resonance and radiation performance with very compact size on low-cost substrate while covering the whole UWB. Finally, the simulated resonating and radiation characteristics have been validated with the measured characteristics of the fabricated prototype and the results are quite promising.

Shuffled frog Leaping algorithm based circular patterns loaded ring shaped fractal antenna for multistandard wireless applications

This paper describes the design and experimental behavior of a 2nd iterated modified Square Ring Shaped Fractal Antenna (SRSFA). The radiator geometry consists of three symmetrical square-shaped rings loaded with circular patterns at the corners. The designed fractal patch is placed on a slot loaded ground structure. The electrical dimensions possessed by the realized structure are 0.15λ0 x 0.15λ0 x 0.080 λ0, and the whole antenna is implemented using FR4 substrate. In this design, transmission line width ‘WF’ and position ‘FP’ are optimized using Shuffled Frog Leaping Algorithm (SFLA) and Artificial Bee Colony (ABC) strategies. It has been examined that the optimized values of ‘WF’ and ‘FP’ using SFLA and ABC are 2.6 and 12.4 mm, and 3.2 and 15.9 mm, respectively. Results reveal that SFLA offers better solution quality and convergence speed than ABC. Further, experimental analysis has been demonstrated to effectively illustrate the recommended fractal approach. The equivalent circuit of the designed structure is implemented successfully. The conducted measurements show that for VSWR ≤ 2, the fabricated structure produces six resonance points with adorable S11 values. The resonances appear at 1.53 GHz (1.35–1.67 GHz), 4.30 GHz (4.20–4.40 GHz), 7.58 GHz (7.43–7.70 GHz), 11.35 GHz (10.37–11.58 GHz), 14.03 GHz (13.85–14.35 GHz), and 15.93 GHz (15.43–16.25 GHz). The examined −10 dB impedance bandwidth at the respective resonance points is 20.9 %, 4.6 %, 3.5 %, 11.3 %, 2.9 %, and 5.23 %. Healthy concordance is noticed among the experimental measurements and electromagnetic simulations. The demonstrated radiation patterns are arbitrary bidirectional/omnidirectional at the respective resonances with good stability. Additionally, the offered gain is within the range of 4.91–7.00 dB. Hence, by utilizing the above-mentioned approaches, miniaturization of 65 % has been achieved. Practical outcomes suggest that the introduced prototype exhibiting multiband behavior, can be effectively applied in Radio location, Radio astronomy, Long-range tracking, Weather location Broadcasting, Search for extra-terrestrial intelligence, Radar altimeters, High resolution mapping, Aeronavigation, and Miscellaneous Radars.

A parasitic patch loaded staircase shaped UWB MIMO antenna having notch band for WBAN applications

A staircase-shaped quasi-fractal antenna is presented to meet the requirements of compact electronics operating in UWB or E-UWB spectrum. A conventional broadband monopole antenna is converted into UWB antenna utilizing three iterations of fractal patches. The resultant antenna offers wide impedance bandwidth ranges 2.3–17.8 GHz, having a notch band at 6.1–7.2 GHz. Afterwards, a two-port MIMO antenna is created by placing the second element orthogonally with an edge-to-edge distance of 8.5 mm, that is λ/15 where λ corresponds to free space wavelength at the lowest cut-off frequency. Hereafter, a meandered line-shaped stub is inserted to reduce the mutual coupling between closely spaced MIMO elements to less than −25 dB. As the intended application of the proposed work is On-body, Specific Absorption Rate (SAR) analyses are carried out at 2.4, 5.8 and 8 GHz, showing an acceptable range for both 1-g and 10-g averaged tissues standards. Moreover, various parameters of the MIMO antenna are studied, and a comparison is made between simulated and measured results as well as those of the state of the art.

Analysis of Graphene Pythagoras Tree Fractal Antenna with Thin SiO2 Substrate in Terahertz Regime

Abstract The Pythagoras Tree Fractal patch is considered on a SiO2 substrate thickness of 1.5 µm to radiate at four frequencies of 4.975THz, 5.38THz, 6.73THz, and 7.61THz with Voltage Standing Wave Ratio (VSWR) ≤ 2. This is a very creative fractal design of a multiband THz antenna, based on a very thin graphene layer, the study proved a value in terms of high radiation efficiency and high gain, at the level of current research we made a comparison study where the design has evidently huge potential regarding applicability for telecommunication technology in the terahertz regime. The demand for high-performance terahertz (THz) antennas has increased significantly in recent years due to their potential applications in various fields such as medical imaging, security screening, and wireless communications. In this paper, the authors present an analysis of a graphene Pythagoras Tree Fractal (GPTF) antenna with a thin SiO2 substrate for THz regime. The GPTF antenna is designed using a fractal geometry approach, which provides multiple resonant frequencies and enhances the overall radiation efficiency. The thin SiO2 substrate is used to reduce the substrate losses and improve the radiation performance of the antenna. The authors use the Finite-Difference Time-Domain (FDTD) software to simulate the performance of the proposed antenna. The results show that the proposed antenna exhibits high gain, low return loss, and wide bandwidth, making it a promising candidate for THz applications.

On the devolvement of fractal antenna for IoT applications

A fractal patch antenna is designed and fabricated on FR4-epoxy substrate for Internet of Things (IoT) applications. Minkowski fractal has been used in the design of radiating element of antenna and slots are incorporated in the partial ground structure. The proposed antenna is miniaturized by 65% in terms of resonating frequency using Minkowski fractal. The proposed structure of antenna has an overall size of 60× 40 ×1.6 mm3. The antenna resonates at 1.223, 1.58, 2.69, and at 3.54 GHz. It exhibits an impedance bandwidth of 0.11 (1.16–1.27) GHz, 0.23 (1.47–1.70) GHz, and 4.5 (1.99–6.49) GHz. The proposed antenna has a peak gain of 3.4 dBi. The key benefits of the proposed antenna are: simple structure, improved performance characteristics, and its usefulness for applications such as Global Positioning System (GPS), Radar Altimeter, Public Safety Applications, and 5G communications in sub-6 GHz band. The simulated results of the proposed fractal antenna have been verified experimentally. The results are highly convincing.

Modeling and Simulation of a Micro-Strip Patch Antenna in Pentagonal Fractal Geometry

The antenna is an important element in the field of communication for transmitting and receivinginformation in the form of electromagnetic waves, it is also used in several fields such as detection systems, satellites and surveillance aircraft, communications networks and GPS automobiles and satellite communications through the system. The design of the antennas using the A-HFSS software "Ansoft- High Frequency Structure Simulator" is essentially based on the variation of the shape of the antenna and its conductive material, the nature and the thickness of the substrate in order to have a structure that resonates in the desired frequencies for applications precise.The goal of this work is to study and design a micro strip patch antenna in fractal geometry, regarding thecharacteristics such as the reflection coefficients, the gain and the radiation implemented in the environment HFSS software. The patch antenna is characterized by its small size, low cost, easy manufacturing and network connectivity. Despite its space-saving appearance, it retains the electromagnetic properties that ensure the device connectivity. We have compared the patch antenna in pentagonal and fractal pentagonal geometry in 1D to 3D pentagonal antenna array on the resonance frequency fed by a micro-strip line in order to have the best characteristics of these antennas; the bandwidth and the directivity of this antenna, using the electromagnetic simulation tool in the frequency domain CST MICROWAVE STUDIO.The information’s will reach: -The resonance frequency is higher for a normal patch antenna compared to that of a fractal patch antenna.- There is a presence of interferences due to the correctly destination.- The gain radiation pattern is a dipole (isotropic antenna) in the fractal antenna.– The bandwidth is wider for a fractal patch antenna compared to that of a normal patch antenna.

An ultrawideband Koch fractal patch antenna

PurposeCompact and wideband antennas are the need of modern wireless systems that preferably work with compact, low-profile and easy-to-install devices that provide a wider coverage of operating frequencies. The purpose of this paper is to propose a novel compact and ultrawideband (UWB) microstrip patch antenna intended for high frequency wireless applications.Design/methodology/approachA square microstrip patch antenna was initially modeled on finite element method-based electromagnetic simulation tool high frequency structure simulator. It was then loaded with a rectangular slit and Koch snowflake-shaped fractal notches for bandwidth enhancement. The fabricated prototype was tested by using vector network analyzer from Agilent Technologies, N5247A, Santa Clara, California, United States (US).FindingsThe designed Koch fractal patch antenna is highly compact with dimensions of 10 × 10 mm only and possesses UWB characteristics with multiple resonances in the operating band. The −10 dB measured impedance bandwidth was observed to be approximately 13.65 GHz in the frequency range (23.20–36.85 GHz).Originality/valueOwing to its simple and compact structure, positive and substantial gain values, high radiation efficiency and stable radiation patterns throughout the frequency band of interest, the proposed antenna is a suitable candidate for high frequency wireless applications in the K (18–27 GHz) and Ka (26.5–40 GHz) microwave bands.

Design of compact fractal patch antenna for X/Ku/K‐band applications

SummaryThis paper presents a fractal‐based compact new monopole antenna for wideband applications. The miniaturization has been achieved by incorporating Minkowski and Koch‐snowflake fractals. The proposed antenna design is etched on top of Rogers RT/5880 dielectric material with a dimension of mm2. The antenna is designed, analyzed, fabricated, and tested in the laboratory. The proposed geometry operates over a 8.62–22.40 GHz with fractional bandwidth (FBW) of 88.84% and VSWR is less than 2. The proposed monopole antenna exhibits nearly omnidirectional radiation patterns over the entire resonating band with a gain of 1–2.91 dBi and a radiation efficiency of more than 60.5%. Also, the measured results of the prototype make an excellent agreement with the simulated counterpart. Further, the antenna gives good time‐domain characteristics. Therefore, the proposed miniaturized antenna can be used in X/Ku/K‐band applications.

A High-gain, Low-profile Filtering Antenna Based on a Novel Metasurface

In this paper, a filtering antenna based on a metasurface is designed using slot-coupled feeding, and the metasurface unit is a fractal pattern. Replacing the rectangular patch on the metasurface with a fractal patch can introduce a radiation zero point on the upper sideband of the antenna, thereby enhancing the sideband selectivity. In addition, the current is reversed by loading shorting pin, and a radiation zero point is also introduced in the lower sideband. After measurement, the -10 dB impedance bandwidth of the filtering antenna is 23.6% (3.22-4.08 GHz), and the average antenna gain in the passband is 8.1 dBi. The filtering antenna does not involve an additional filter circuit, has a simple structure, and a small size, and ideally eliminates insertion loss. To verify, the real object was made and tested and found that the reflection coefficient, pattern, gain, etc. were in good agreement with the simulation results, it can be applied to the 5G communication frequency band.

Planar nested square fractal patch antenna for multi-band wireless applications

Planar nested square fractal patch antenna for multi-band wireless applications

Design of Optimized Koch Based Fractal Patch Antenna for Multiband Wireless Applications

An optimized Koch based fractal patch antenna with twin lower leafs has been designed for appropriate wireless communication applications and capable of exhibiting penta-band behavior. The proposed structure has been created by introducing modified Koch curve on a rhombus shaped fractal patch having compact dimensions of 60 mm×50 mm×1.6 mm with defected ground structure. The reflection coefficient (S11) values of the proposed antenna are -11.97 dB, -20.29 dB, - 25.38 dB, -13.91 dB and -23.48 dB at resonating frequencies of 2.8649 GHz, 6.3514 GHz, 7.1622 GHz, 8.2973 GHz, and 8.9459 GHz, respectively. It has values of VSWR at all resonating frequencies within acceptable range of 1 to 2. The prototype of the proposed structure has been designed on easily available and low cost FR4 epoxy substrate material. The bandwidths of 1.39 GHz, 3.30 GHz, 10.19 GHz, 1.93 GHz and 2.23 GHz has been obtained at all resonating frequencies. The measured results has been analyzed and compared with simulated results and bears a close approximation. The developed prototype can be utilized for applications in S, C, and X frequency band which can further be used for various communication applications like radar, satellite communication and wireless computer networks.

A Novel Fractal Patch Antenna Using Defected Ground Structure (DGS) with High Isolation for 5G Applications

A Novel Fractal Patch Antenna Using Defected Ground Structure (DGS) with High Isolation for 5G Applications

Wideband improvement for hybrid plasmonic fractal patch nanoantenna

A wideband improvement for hybrid plasmonic fractal patch nanoantenna is presented for use in intra/inter chip optical interconnects. The suggested fractal patch antenna covering a part of U-band (1625-1675), L-band (1565-1625nm), C-band (1530-¬1565nm), S-band (1460-1530nm), E-band (1360-1460nm) and most of O-band (1260-1360nm) optical communication bands. The proposed antenna has a promising future use in inter and intra chip optical communications to eliminate electrical interconnection limitations such as interconnect density, power consumption and also increasing data rate. The performance of this antenna has been evaluated using full wave simulation computer simulation technology (CST) Microwave software. The impedance bandwidth is largely enhanced by applying rectangular fractal cuts to the both sides of patch. The proposed antenna achieves a wider bandwidth from 168 THz to 228 THz (B.W.=60 THz), which is about 8 times greater the bandwidth of reference antenna with a good gain and more than 95% radiation efficiency throughout the operational bandwidth.

Fractal geometry-based chakra-shaped microstrip patch antenna array for vehicular communications under 5G environments

ABSTRACT In this paper, fractal geometry-based two-printed antenna structures are proposed for vehicular communication in 5G wireless communication networks. Initially, a 48 × 39 mm2 single element fractal patch antenna is designed and tested which shows dual-band resonance at around 28.1 and 32.5 GHz. In order to improve different antenna characteristic number of fractal radiating elements have been increased to four and constructed an array of patches such that it can be used for multiple applications in the field of vehicular communications. The proposed array model is fabricated on a Rogers RT duroid 5880tm material of size 115 × 82 mm2 and tested using Agilent Technologies N5247A VNA. The measured results confirm the validity of the designed model for intended applications. The proposed array antenna operates at distinct quintuple bands in the frequency range of 25–36 GHz for vehicular communication within the proposed lower fifth generation (5G) channel. The proposed array configuration shows a good peak gain of 6.72 dB within the operating bands.

A fully flexible, high gain saw-tooth-shaped boundary fractal wearable patch antenna for WBAN applications

AbstractA flexible and high gain saw-tooth-shaped boundary fractal wearable antenna is anticipated for WBAN applications. A square shape is converted to the saw-tooth-shaped boundary by sequentially rotating the square at an angle of 45° and overlaid on one another and repeated the same for three iterations. The geometry is built on a flexible jeans substrate, and the total size of the anticipated antenna is 0.583λ × 0.583λ × 0.02λ at 2.4 GHz. A prototype has been made to test its suitability for wearable applications' gain, bandwidth, and efficiency. The results revealed that the proposed antenna provides an impedance bandwidth of 4.2% and a peak gain of 5.76 dBi at the 2.45 GHz ISM band. The anticipated antenna is wrapped around foam cylinders of radii 70 and 50 mm to test the stability and deformability of its performance. The full ground plane isolates the antenna from the human body contributing to the lower SAR values. The simulated maximum achieved specific absorption rate (SAR) of 0.3025 and 1.16 W/kg for 10 and 1 g of average tissue for the input power of 100 mW, respectively, found within the standards as per FCC. The peak gain, compact size, and SAR permanence made the anticipated antenna a worthy candidate for wearable on/off body applications.

Analysis of 2 × 2 MIMO array loaded by artificial magnetic conductor with improved gain, isolation, and bandwidth using equivalent transmission line model for indoor wireless base station

A low profile printed dipole antenna (PDA) backed by broadband Giuseppe Peano fractal artificial magnetic conductor (AMC) is introduced for wireless communications. First, a suggested PDA with a pair of microstrip dipoles excited by an E-shaped microstrip feedline is used to expand the bandwidth in the range of 5.96–7.04 GHz (S11 ≤ −10 dB). Then, the suggested Giuseppe Peano fractal AMC surface as a reflector of the antenna is inserted into the PDA to gain improved radiation efficiency. The PDA with the 6 × 6 Giuseppe Peano AMC array exhibits −10 dB measured impedance bandwidth of 4.95–7.05 GHz (35%) for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The suggested PDA with AMC compared to the PDA without AMC exhibits a size reduction of 38%, enhanced gain up to 8.2 dBi, and excellent impedance matching (at least −20 dB) with directional radiation patterns. The novel AMC unit cell is realized based on the Giuseppe Peano fractal patch to operate at 6.10 GHz with an AMC bandwidth of 5.15–7.10 GHz (32%). Besides, by loading 12 × 12 AMC reflector into the four-element array of PDA, low profile wideband structure with enhanced radiation properties are achieved. The measured results show the broad bandwidths of 5–7 GHz for all elements with enhanced gains and good isolations between the elements (more than 24 dB) for multiple-input multiple-output (MIMO) systems.

Application of Selected Fractal Geometry Resonators in Microstrip Strain Sensors

Until now, strain gauges, fiber optic sensors, magnetic sensors, and piezoelectric sensors have been used for strain measurements. In recent years, the idea of using microstrip antennas in strain measurement applications has emerged. One of the key requirements for deformation sensors is the ability to mount them on small-size elements (therefore the size of these sensors is crucial). The possible way to miniaturize microstrip sensors is the application of appropriate patch geometry, e.g. fractal geometry. In this article application of various fractal patch geometries in microstrip strain sensors were investigated. All sensors were designed for the same operating frequency <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}_{\textbf {r}} =2.725$ </tex-math></inline-formula> GHz and on the same laminate. This approach showed how the influence of a specific geometry affects the sensitivity and the transducer size. The Sierpinski carpet, the Sierpinski triangle, the Sierpinski curve, and the combination of the Koch curve and the Sierpinski carpet were used to obtain the fractal geometry and miniaturize the sensor dimensions. They have been compared with the widely used rectangular patch. Numerical and experimental analyzes for the proposed sensors were carried out. The best solution to this problem was to use a combination of the Koch curve and the Sierpinski carpet. This fractal geometry, compared to a rectangular patch, enables the reduction of the patch size by 70% while reducing the sensitivity by 26%.