Fractal Antenna Research Articles

High-Gain Multi-Band Koch Fractal FSS Antenna for Sub-6 GHz Applications

This study introduces a novel antenna based on the binary operation of a modified circular patch in conjunction with the Koch fractal. The antenna is intended for applications in the sub-6 GHz band, partial C-band, and X-band. The low-cost antenna is fabricated on a 1.6-mm-thick FR-4 substrate. A frequency-selective surface (FSS) is used to overcome the decreased values of the gain and bandwidth due to the fractal operations. The introduced split ring resonator (SRR) and the antenna substrate dimension reduction reduce the bandwidth and antenna gain. The air gap between the FSS and the antenna not only enhances the antenna gain but also controls the frequency tuning at the design frequency. The antenna size is miniaturized to 36.67%. A monopole antenna ground loaded with an SRR results in improved closest tuning (3.44 GHz) near the design frequency. The antenna achieves a peak gain of 9.37 dBi in this band. The FSS-based antenna results in a 4.65 dBi improvement in the gain value with the FSS. The measured and simulated plots exhibit an excellent match with each other in all three frequency bands at 2.96–4.72 GHz. These bands cover Wi-MAX (3.5 GHz), sub-6 GHz n77 (3300–3800 MHz), n78 (3300–4200 MHz), and approximately n79 (4400–4990 MHz), in addition to C-band applications.

Cross-complementary photonic band gap structure-based terahertz fractal antenna for detection of cardiac troponins

Cross-complementary photonic band gap structure-based terahertz fractal antenna for detection of cardiac troponins

Design of a Tri-band Minkowski Fractal MIMO Antenna for FR2 5G Applications

The growing importance of fifth-generation (5G) communication technologies for the Internet-of-Things have made it necessary to design multi-element antennas that operate within the millimetre-wave spectrum. However, simultaneously achieving multiple operating frequencies, high gain and good isolation between the elements of such small-sized antennas is a challenging task. In this research, a composite right/left hand millimetre-wave fractal antenna was designed for 5G mobile terminals, in order to simultaneously satisfy these key design goals. This aim was accomplished by designing a 2 x 2 multiple-input, multiple output (MIMO) antenna based on the second-order Minkowski fractal using an electromagnetics simulation software, Computer Simulation Technology (CST) Studio Suite ®. Two composite-right/left hand structures were included on the reverse side of the antenna, to reduce the coupling between the MIMO antenna elements. Simulation results show that the designed antenna operates at three frequency bands within the millimetre-wave spectrum, namely 25.52 GHz – 28.23 GHz, 36.5 GHz – 37.5 GHz, and 47.7 GHz – 49.7 GHz. The maximum antenna gains at these three bands are 6.9 dBi, 7.5 dBi, and 6.0 dBi, respectively. Also, good isolation is realized between the antenna elements at the operating frequencies, with a minimum value of 10.8 dB. With a spacing of 0.03λ between the MIMO antenna elements, the overall size of the designed antenna was 30 mm x 12 mm x 0.508 mm, which compares positively with other related fractal antenna designs. The designed antenna shows good prospects for integration into various mobile terminal devices to aid 5G-based millimetre-wave communications.

Multilayer multiband hybrid fractal antenna for public safety and 5G Sub-6 GHz bands

In this work, a multiband hybrid fractal antenna is developed for public safety and 5G Sub-6 GHz bands. Proposed antenna design is designed, analyzed, and optimized using HFSS simulator. Radiating element of the proposed antenna consists of Hybrid Fractal shape which is designed using Koch and Hilbert curve fractal geometry. Hybrid Fractal Antenna (HFA) is designed on a Multilayer FR4 substrate which has an overall size of 0.22 × 0.47 × 0.044 ƛ3. Parametric analysis of the proposed design is done to get the optimum results. Proposed HFA resonates at 2.64 GHz (2.34–2.80 GHz), 3.87, 4.54, 5.02, 5.35 GHz (3.73–5.55 GHz), and 6.42 GHz (5.70–6.72 GHz) with a gain of 4.2, 0.9, 2.9, 3.3, 4.6, and 3.7 dBi respectively. The proposed HFA is useful for 5G bands such as: N7 band, N38 band, N40 band, N41 band, N47 band, N53 band, N79 band, N90 band and N93 band, and also useful for public safety band (4.9 GHz). Prototype of the proposed HFA is fabricated and tested in lab for the verification of simulated results. The results show good performance in terms of reflection coefficient, gain, and bandwidth. Measured results are in good agreement with the simulated results.

Koch Curves and Hexagonal Ring-Shaped Geometry Based Ultra-Wideband Fractal Antenna

Koch Curves and Hexagonal Ring-Shaped Geometry Based Ultra-Wideband Fractal Antenna

Reconfigurable fractal antennas for future wireless applications: A comprehensive review

SummaryReconfigurable fractal antenna (RFA) design is always necessary for the continued development of wireless communication systems as the antenna is playing a vital part in device performance. The need for efficient radiators that are compact, low‐profile, inexpensive, and low weight has attracted scientists for their research works. As a result, numerous ideas were put forward by the researchers to attempt to resolve these problems by utilizing various kinds of fractal and reconfigurable antennas as well as their combinations. However, it is challenging to have a clear and transparent review of the various works with a large variety of solutions and their uniqueness. The advanced RFA design for wireless applications is reviewed in this study together with its most recent and pertinent counterparts. In Koch RFA, bandwidths enable selective bands spanning 1–6 GHz frequency range. Further, in band RFA design, the overall bandwidth ranges from 1.45 to 4.52 GHz (103%) with low gain; on the other hand, the crescent RFA achieves 5.67 dBi peak gain. Furthermore, in polarization RFA, the ARBWs are 17.61% (2.2–2.62 GHz) and 8.69% (2.91–3.18 GHz). The Hilbert RFA operates at 0.9 and 2.45 GHz with gains of 3.1 and 7 dBi, respectively. This article investigates a comprehensive review of the requirements for RFAs for wireless applications. Furthermore, a comparative study on different reconfigurability with switching techniques, fractal geometries, various RFA design approaches to enhance device performance, and their significance is discussed. Existing research challenges and future directions are also discussed as part of this article.

Invasive weed optimization based compact hybridized fractal antenna design for RF energy harvesting and multifunctional wireless applications

This paper describes the optimal design and analysis of compact multiband Hybrid Fractal Antenna using Invasive Weed Optimization (HFAIWO). The configured structure involves the fusion of Minkowski, Sierpinski carpet and Giuseppe Peano in a coherent manner. The two-iterative conglomerated fractal antenna is realized physically by considering FR4 epoxy material (dielectric constant, εr = 4.4 and mass density = 1,900 kg/m3). The volumetric dimensions of the fabricated prototype are 36 x 36 x 1.6 mm3. In the designing process, the geometrical descriptors, namely, feedline width ‘WF’ and ground plane dimension ‘LG’ are optimized specifically using Invasive Weed Optimization (IWO) and Harmony Search Algorithm (HSA) strategies. The optimal solution is searched by changing the descriptor values under a set of practical constraints. The examined values of ‘WF’ and ‘LG’ using IWO and HSA are 3 and 31 mm, and 2.6 and 28.7 mm, respectively. Comparative results reveal that IWO offers superior solution quality and convergence than HSA. Afterwards, experimentation of the Projected HFAIWO is done to justify the recommended fractal hybridization approach. Measurements reveal that for VSWR ≤ 2, the fabricated structure produces nine resonance points (1.84, 3.99, 5.15, 5.55, 6.30, 6.58, 8.00, 9.29, and 12.01 GHz) with appreciable gain values. At the respective resonance points, the −10 dB impedance bandwidth is 3.9 %, 3.1 %, 2.1 %, 2.2 %, 1.4 %, 1.2 %, 6.9 %, 1.2 %, and 12.23 %. The provided radiation patterns are arbitrary bidirectional/omnidirectional. By applying the above-said approaches, the radiator size is reduced by 54 %. Importantly, the constructed structure covers two important bands i.e. 1.84 GHz (GSM 1800 band, downlink) and 5.55 GHz (WLAN (Lower) 5.150–5.725 GHz) associated with energy harvesting applications. The practical outcomes suggest that the introduced prototype is a proficient candidate for energy harvesting systems, Satellite communication for downlink, Long range tracking, Battlefield surveillance, Digital broadcast satellite service, Weather Radar, and Maritime navigation radar.

Multi-band microbolometer in CMOS technology

Multi-spectral imaging enhances the information diversity of the object with complex, expensive, and low integrated components. Here, we demonstrated an antenna-coupled microbolometric detector in complementary metal-oxide-semiconductor (CMOS) technology, utilizing SiO2 absorption and L-shaped fractal antenna to achieve multi-band detection from infrared (IR) to terahertz (THz). Experimental results demonstrate that the detector can achieve high sensitivity detection in both THz and IR bands, with the maximum detectivity of 5 (108 cm·Hz1/2/W @305 GHz and 7 (108 cm·Hz1/2/W @8.55 µm, respectively. The presented multi-spectral detector is easily implementable in integrated circuit process, conducive to high-density, low-cost, and high-performance array imaging.

Development a novel design of miniaturized heptagonal Koch fractal wide band antenna for 5G mm wave and IoT applications

The object of the study is a compact heptagonal broadband antenna specially designed for use in the 5G millimeter band using Koch fractals to improve performance. As a result of the study, the most important problem of achieving higher gain, improving bandwidth and reducing interference at higher frequencies, which is necessary for the effective functioning of 5G networks, was solved. As a result, the maximum realized gain of 5 dB was obtained at a frequency of 27.58 GHz with an impressive bandwidth in the range from 26.5 to 40 GHz. The use of Koch fractal geometry and defective ground planes significantly improves impedance matching and expands bandwidth, which explains the excellent antenna performance compared to traditional designs. The features and distinguishing features of the results obtained, thanks to which they allowed solving the problem under study, are its compact dimensions (only 9 mm by 9 mm) and the ability to maintain VSWR at a level of less than 2 in the entire frequency spectrum. These features make the antenna particularly suitable for millimeter-band integration and flexible applications such as portable devices and wearable home appliances. The field of practical application of the results includes integration into portable and wearable devices, improving the performance and connectivity of Internet of Things applications. The conditions of practical use require compliance with 5G network standards and compatibility with millimeter-wave technologies. This characterizes the antenna as a significant achievement in antenna technology, demonstrating its potential for widespread adoption in next-generation wireless communication systems and paving the way for more reliable and high-performance wireless networks

A hexagonal shape fractal flexible UWB antenna based on jeans material for healthcare applications

This work aims to provide a compact, flexible, lightweight ultra-wideband antenna design with enhanced bandwidth for medical applications. The proposed antenna features fractal geometry and is made by iterating a hexagonal slot within a circular copper construction. The basic radiator’s partial ground plane is defective with a slit at the centre and a down ramp on both sides of the plane. A stub in the feed line improves impedance matching and provides enhanced −10dB bandwidth of 10.6 GHz (1.9 GHz to 12.5 GHz). The antenna is built on a black jeans textile substrate of dielectric constant 1.7 and size of 48 mm × 36 mm × 1.7 mm . The maximum gain of 6.75 dB at the frequency of 2.3 GHz is reported. In the operational band, the developed antenna provides steady radiation properties. Furthermore, the antenna has been verified for use in practical applications by setting up the proposed antenna as a receiver with an NRF24L01 wireless transceiver module and given coverage up to 50 feet in an open environment. The designed prototype is analysed for flexibility with different bending radii. A SAR analysis is also carried out for 1 gram and 10-gram of tissue along with the extensive time domain analysis for wearable UWB applications.

A compact ultra-wide band fractal antenna for breast cancer detection applications

A compact ultra-wide band antenna for breast cancer detection in bio-medical applications is presented in this study. The proposed antenna is printed on 1.6 mm thick FR4 substrate with a dielectric constant of 4.6 and tangential loss of 0.02. The uniform ground plane on the substrate (PCB) has been altered by shortening its length and making minimal changes to its side edges in order to improve overall bandwidth. The suggested antenna is functioning from 3 to 10.2 GHz which covers the ultra-wide band recommended by Federal Communication Commission (FCC) over the 10 dB impedance bandwidth. Additionally, the antenna has a significant overall gain of 3.2 dBi and an overall radiation efficiency of between 89 % and 92 %. Furthermore, the antenna maintains a uniform radiation pattern across its operating band. Parametric research has been conducted on the different parameters to tune the antenna into the required operating band, and placement analysis of the antenna is then investigated by assessing specific absorption rate (SAR).

Drone Shaped Fractal Antenna with Defected Ground Structure for RF Energy Harvesting Applications

A proposed multiband drone shaped fractal antenna (Antenna-1) is introduced in this paper that targets the most required frequencies used for radio frequency energy harvesting applications, including WLAN-2.4G, WLAN-5G, WLAN-6G, Mobile DCS1700, Mobile LTE and WIMAX services. A novel fractal shape is designed and combined with a standard square geometrical shape in order to implement the front patch of the antenna. The antenna is simulated with CST Studio Suite software and fabricated on FR-4 substrate. Different antenna stages with parametric study and optimization were implemented to get the best performance from the drone shape fractal antenna. The multiband (Antenna-1) supports six resonate frequencies (1.7155 GHz, 2.424 GHz, 3.36 GHz, 3.789 GHz, 5.843 GHz, 6.886 GHz) with peak gain of (2.83 dBi) at the frequency 2.45 GHz and a maximum bandwidth of (0.4281 GHz) at the frequency 5.8 GHz that make it a suitable antenna for radio frequency energy harvesting applications.

Design and Analysis of Microstrip Sierpinski Fractal Antenna for Wireless application

This paper describes a novel design for a microstrip fractal antenna based on the Sierpinski triangle shape. It is built on a FR4 substrate and operates in the 5.5 GHz frequency range. The proposed antenna is designed and validated using ANSYS Electronic Desktop's High Frequency Structure Simulator (HFSS). The simulated results show good performance in terms of radiation pattern, gain and input impedance. This proposed antenna can be widely used in wireless communication equipment that is progressing towards miniaturization and high frequency. The antenna designed gives a return loss of -29 dB at 5.53GHz. It has a gain of 0.85 dB and directivity of 1.8dB.

Dual Polarized Gain Enrichment of a Low-Cost Multi-Band Circular Fractal Antenna Using Tunable Stacked FSS for Wireless Applications

Dual Polarized Gain Enrichment of a Low-Cost Multi-Band Circular Fractal Antenna Using Tunable Stacked FSS for Wireless Applications

A design of compact wideband substrate integrated waveguide fractal koch surface slot antenna for Ka‐band applications

SummaryThis article analyses a substrate integrated waveguide (SIW) fractal koch surface (FKS) slot antenna performance for Ka‐band applications. This FKS slot shape is obtained by modifying the conventional rectangular slot with the first iteration of the FKS method. The resultant FKS slot behaves as a radiator in the provided space. A single‐ and two‐element FKS slotted SIW antenna characteristics are analysed on a 20 mil thick RT/Duroid 5880 substrate and compared with the conventional rectangular slot. The proposed antenna with dimensions mm3 achieves an impedance bandwidth from 27.4 to 32.1 GHz with a fractional bandwidth of 15.79% and achieves a gain of 8.3 dBi in broadside direction by improving space filling factor in SIW structure. The prototype of the SIW‐fed FKS slotted antenna array measurement results is satisfactory with the simulation results.

Compact novel circular shaped fractal quad-port MIMO antenna loaded with DGS and stub for 6G, WiMax and weather monitoring

Compact novel circular shaped fractal quad-port MIMO antenna loaded with DGS and stub for 6G, WiMax and weather monitoring

Hybrid β Ω-indexing based fractal antenna for multi-band wireless applications

Hybrid β Ω-indexing based fractal antenna for multi-band wireless applications

Super-wideband fractal antenna of two-arm structure with broadband balun

ABSTRACT A balanced two-arm antenna has been proposed for super-wideband (SWB) operation to work efficiently over the frequency range (2.95 − 34 GHz ). The antenna proposed for SWB operation can be considered as composed of two main parts. The first part is the radiating surface of the antenna and is composed of two-arms leading to a balanced antenna structure. For wideband operation, each arm has a double-fractal (angular/radial) structure. The second part of the antenna structure is the wideband feeding balun that is responsible for realising maximum power transfer and impedance matching while feeding the balanced radiating two-arm structure from the conventional unbalanced coaxial line. A prototype has been fabricated for experimental characterisation of the proposed antenna. Both the simulation results and the experimental measurements come in good agreement with each other showing that the proposed antenna can be good candidate for many super-wideband applications of future generations of mobile communications. The proposed antenna has overall dimensions of 40.0 mm × 21.0 mm × 1.5 mm . It is shown by simulation and measurement that the proposed antenna has %BW of 168 % , RBW of 11.5 : 1 , and BDR of 2015 . The maximum gain ranges between 2.3 and 6.2 dBi. The radiation efficiency is greater than 98% over the frequency range ( 2 − 24 GHz ) and is greater than 85% over the frequency range ( 24 − 34 GHz ).

UN AMPLIO ESPECTRO DE SUSTRATO HEXAGONAL DE OCTAVO MODO PARA APLICACIONES EN BANDA C, S, X

The following article explains how to make a basic ultra-wide bandwidth (UBW) wearable fractal antenna. The antenna is printed on denim fabric with a dielectric constant of 1.7 and a loss tangent of 0.02. The suggested antenna is 45 x 44.92 x 0.5 mm3. The antenna is fed by an inserted microstrip line with a decreased ground structure. It operates at ultrawide band frequencies of 4.36 GHz to 11.12 GHz. The antenna offers an omnidirectional radiation pattern with a gain of more than 2.4 dBi across the entire working band... It achieves a bandwidth of 6767 MHz. The proposed antenna possesses key characteristics such as a simple structure, ease of fabrication, stable omnidirectional radiation pattern, reasonable gain, and directivity, which make it suitable for applications in the C, S, and X bands. Keywords: Textile antenna, UWB, denim fabric, flexible antenna, denim substrate

UWB-MIMO 4-Port Fractal Antenna with Reduced Mutual Coupling

Abstract: UWB MIMO antenna loaded structure Mutual coupling between the four radiating elements is obtained to be less than - 25 db. The patterns of radiation are stable over the operating range and a peak gain of 4.5 dB is obtained at 7.5GHz and Return loss is obtained less than 10dB. Simulation is conducted using HFSS simulation tool and printed on a 30 X 30 X 1.6 mm3 FR4 material. 4 linear SRR structures are used between adjacent elements to ensure good isolation. MIMO antenna with grounded stubs and fractal geometry are used to improve isolation and to achieve wide band phenomena. UWB-MIMO antenna using to achieve better isolation. The UWB MIMO 4-port fractal antenna combines the characteristics of ultra-wideband operation, multiple input multiple output capability, four-port configuration for simultaneous data streams, and a fractal antenna design for wide bandwidth and compact size. This makes it suitable for high-speed, reliable communication in applications requiring UWB technology, such as high-speed data transfer, localization, and radar systems. By integrating a copper rectangular plane between ports, interference and crosstalk are minimized, enhancing the antenna's capability to handle multiple input and output signals efficiently. This innovative design approach not only improves isolation but also contributes to the antenna's overall effectiveness in various communication applications.