Fractal Microstrip Antenna Research Articles

Compact and miniaturized metamaterial-based microstrip fractal antenna with reconfigurable qualification

Design procedure of a small dual-band antenna based on composite right/left-handed (CRLH) transmission line is proposed in this article. The conventional microstrip patch is assumed as a primary antenna and then, Minkowski-like fractal geometry is applied. The antenna has a compact size of 20 × 20 mm2, and operates efficiently at 4.4 GHz and 6.1 GHz. The antenna provides high gain of 3.8 dB and 6.2 dB in the two operating bands, respectively. It also has an omnidirectional radiation pattern with low cross-polarization level. The effect of the fractal structure along with CRLH transmission line concepton the miniaturization and multiband performance of the antenna have been studied. The related results show the accuracy of the theoretical studies and good agreement between simulated and measured results, which verify that the antenna is a suitable candidate for wireless communication applications.

Koch–Sierpinski Fractal Microstrip antenna for C/X/Ku-band applications

ABSTRACTThis article is based on dual fractal techniques to design the Koch–Sierpinski Fractal Microstrip (KSFM) antenna for wireless applications. The concept of the Koch fractal is applied on the outer periphery of the square-shaped patch and Sierpinski gasket concept on the inner segment of the square-shaped patch to reduce the effect of surface currents. The antenna design involves two degrees of iteration using dual fractal techniques. The antenna is simulated using HFSS software and fabricated. The measurements of antenna parameters are done using a vector network analyser (VNA). The proposed antenna covers multiband resonant frequencies of 5.699 GHz, 10.108 GHz, 11.100 GHz, 15.812 GHz and 17.621 GHz for C-band (4–8 GHz), X-band (8–12 GHz) and Ku-band (12–18 GHz) applications. The antenna achieved better bandwidth at high range of frequencies. Three different substrates were chosen to compare the results of the proposed antenna (Fr4, Rogers RO 4003 and Rogers Ultralam) with the Fr4 substrate achieving the best results. The simulation agreed well with those obtained experimentally.

Design of ultra-wide band fractal microstrip antenna

Design of ultra-wide band fractal microstrip antenna

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.

Design of WLAN/WiMAX band notch super-wideband microstrip fractal antennas

AbstractA super-wideband microstrip fractal antenna is designed with miniaturized dimensions of 21 mm × 23.5 mm × 1 mm and generation of dual rejection bands for WLAN/WiMAX systems has been achieved. The triangular fractal shape slots are placed inside a circular patch and the antenna is miniaturized by using a repetition frequency resonance technique. The proposed antenna frequency range 2.6–40 GHz operates for VSWR of less than 2. Two band rejections for the frequency ranges 5.1–5.8 GHz and 3.4–3.7 GHz are created by one enhanced slot at the feed line and one split-ring resonator at the back of antenna. HFSS 3D software was used for computer simulation. The proposed antenna is fabricated on the FR4 substrate with 1 mm thickness. The measurement data show good agreement with the simulation results.

A complementary Sierpinski gasket fractal antenna array for wireless MIMO portable devices

AbstractThis research work reports the design and development of a novel complementary Sierpinski gasket fractal microstrip antenna array to achieve a good impedance bandwidth and hence support high data rates for 4G/5G MIMO applications. The proposed array is a compact structure (136 mm × 136 mm) designed with complimentary Sierpinski gasket fractal up to two iterations and has a defected ground to improve the antenna's performance. The antenna performance reports an 8.2% bandwidth at the center frequency of 4.94 GHz (4.7434‐5.1514 GHz), a simulated diversity gain of 9.99 allows the proposed array to be well suitable for proposed applications and a directivity of around 5.8 dBi suits good range characteristics. The array designing and optimization is carried out with 3D EM tool CST MWS V'14 using perfect boundary approximations. A simulated low value of envelope correlation coefficient (0.04) indicates that the two antennas in the array provide least interference to each other while radiating. The measured S11 results on a VNA E 5071C show a close match with the simulated results. Thus a compact array size with good bandwidth, radiation characteristics, low ECC and a high diversity gain allow the antenna array to be well suitable for portable MIMO 4G/5G wireless applications specifically for C band and military applications.

Design of Circularly Polarized Modified Minkowski Fractal Based Antenna for UHF RFID Reader Applications

A compact, square shaped microstrip fractal antenna with asymmetrical pairs of T-slits for circularly polarized (CP) radiation and radio frequency identification (RFID) reader applications is proposed and experimentally investigated. Design is based on narrow slit modified Minkowski island fractal geometry. Circular polarization along with size reduction is achieved by inserting four symmetrical pairs of T-slits at the square patch boundary of the single-probe-feed radiator. Proposed geometry is tuned at resonant frequency of 914 MHz by optimization of dimensions of the two T-slits. Compactness of the antenna is achieved by increasing the overall sizes of the slits. Antenna is fabricated on FR4 substrate with a size of 47.2×47.2×1.6 mm3 (0.143λ0 X 0.143λ0 X 0.005λ0) and tested to validate the simulated results. The 3-dB axial-ratio (AR) bandwidth and impedance bandwidth of the proposed antenna design are found to be 7 MHz (911-918 MHz) and 24 MHz (909-933 MHz) respectively. A design equation is develped based on the parametric study that can be used to design a compact antenna with CP for UHF RFID applications covering the frequency range from 887 to 1023 MHz.

Inkjet Printing of Wideband Stacked Microstrip Patch Array Antenna on Ultrathin Flexible Substrates

This paper presents a bandwidth-enhanced, low-cost, compact, inkjet-printed multilayer microstrip fractal patch antenna for integration into flexible and conformal devices. The antenna consists of two layers of patches, with the first layer inkjet-printed directly on a 0.125-mm (only 0.005 of the operating wavelength) Kapton polyimide substrate. On top of it, a 0.12-mm-thick SU-8 polymer is covered. To achieve the desired miniaturization and good impedance match, a Minkowski fractal geometry patch is employed as the second layer inkjet-printed on top of the SU-8 polymer. The proposed antenna has compact dimensions of only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$22\times 31$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and covers 4.79–5.04-GHz frequency spectrum with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11} &lt; -10$ </tex-math></inline-formula> dB. Moreover, a 2-bit <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 4$ </tex-math></inline-formula> phased array antenna (PAA) is constructed, and its scan ability is estimated to demonstrate its potential application in the true-time-delay flexible PAA systems. The prototype is fabricated and tested for impedance and radiation characteristics. The measured and the simulation results show the superiority of the proposed antenna.

Improvement in Depth of Return Loss of Microstrip Antenna for S-Band Applications

For S-band applications, a microstrip fractal antenna is designed by extending narrow impedance bandwidth into wide impedance bandwidth with use of partial ground plane. In the designed fractal antenna, the six elliptical slots in ground plane and two elliptical slots in radiating patch are embedded to improve the depth of return loss. Further, the parametric study is performed on width of microstrip feeding line, position/size of ellipses in radiating patch and ground plane to achieve mismatch loss [Formula: see text] 0.044[Formula: see text]dB and power delivered to antenna 99%, i.e., return loss [Formula: see text][Formula: see text]dB for S-band. The simulated antenna results are obtained using electromagnetic solver software and fabricated antenna results are measured using Vector Network Analyzer Bench MS46322A and they are found to be in good agreement.

An Optimized Wideband High Directive Microstrip Fractal Patch Antenna based on Near-Zero-Index Metamaterial Superstrate

ABSTRACTIn this article, a wideband near-zero-index metamaterial (NZIM) unit cell, for gain improvement of a broadband microstrip fractal patch antenna is proposed and designed. The near-zero refractive index characteristics of metamaterial superstrate is used, which gathers the radiated waves from the source antenna and collimates them toward the normal direction. The reference fractal patch antenna operates at a relatively wide frequency range covering from 2.38 to 3.61 GHz, corresponding to a 40% fractional bandwidth. In order to effectively enhance the broadside gain of the antenna, a proposed unit cell is optimized using invasive weed optimization (IWO) algorithm to have the widest bandwidth at the required frequency band, in which the refractive index is less than unity (approaches zero). A prototype of the antenna was fabricated and tested. Measured results are in good agreement with the simulation. The measured −10 dB relative impedance bandwidth for the loaded antenna with NZIM is found to be 31%. The maximum measured broadside gain is about 3.1 dB higher than that of the reference antenna without NZIM, which corresponds to 86% aperture efficiency.

Compact Fractal Patch Microstrip Antenna Fed by Coplanar Waveguide for Long Term Evolution Communications

Compact Fractal Patch Microstrip Antenna Fed by Coplanar Waveguide for Long Term Evolution Communications

Miniaturized Minkowski-Island Fractal Microstrip Antenna Fed by Proximity Coupling for Wireless Fidelity Application

This paper proposed a new design of Minkowski Island microstrip antenna fed by proximity coupling with partial ground plane. The design was consisted of two layers of substrate, on the top substrate was the antenna patch and on the bottom substrate was the proximity feed line and the partial ground. At the first stage, the normal square patch antenna was mainly designed. Then, the Minkowski patch antenna was designed using 1st iteration technique and 2nd iteration technique. The Minkowski fractal shape slot was embedded in the center of the patch to form a Minkowski Island patch antenna. Using the Minkowski Island fractal technique, the dimension of the patch can be reduced up to 58.7%. The proximity feed line in this design was used to increase the impedance bandwidth, and from the measurement the impedance bandwidth of the proposed antenna was 240 MHz with return loss of -24.54 dB and VSWR of 1.126.

Compact microstrip fractal Koch slot antenna with ELC coupling load for triple band application

In this paper a novel triple band compact microstrip slot antenna is designed, utilizing fractal Koch shape based on metamaterial electric-LC element coupling load. The antenna is fed by CPW line, and it has triple band resonances operating at frequencies of about 1.5, 3.5 and 5.4GHz for GPS, WiMAX and WLAN applications. The bandwidth of antenna at aforementioned frequencies is about 1.9%, 14% and 5% with the gains of −4.5, 3.75 and 5.3dBi respectively. Also it has property of circular polarization for WiMAX application at 3.5GHz. Furthermore metamaterial ELC element based on the metasurface theory, and making variation of the current distribution for circular polarization, made a compact small antenna at 1.5GHz, where the antenna size is reduced to λ/5×λ/5 through coupling on ELC element. The total size of the fractal antenna is assumed 40×40mm, and is designed and fabricated on FR-4. The simulation results are extracted by HFSS commercial software, and compared with experimental results.

Wideband Circularly Polarized Spidron Fractal Slot Antenna with an Embedded Patch

In this communication, a wideband circularly polarized (CP) Spidron fractal microstrip antenna is proposed based on the concept of embedded structures. The proposed antenna is excited by a tapered microstrip feedline. A wide 3 dB axial ratio (AR) bandwidth of 28.81% (3.09–4.13 GHz) is obtained by merging the CP bands of the Spidron fractal slot and patch antennas. In addition, a measured −10 dB reflection bandwidth of 47.25% (2.57–4.16 GHz) is reported. The measured results are in reasonable concurrence with the simulated results. The measured gain varies between 2.12 dBic and 3.56 dBic within the AR bandwidth.

Multi-Edged Wide-Band Rectangular Microstrip Fractal Antenna Array for C- and X-Band Wireless Applications

A low-cost multi-edged rectangular microstrip fractal antenna (RMFA) yielding a huge bandwidth of 8.62[Formula: see text]GHz has been proposed in this paper. The proposed fractal antenna design constitutes a radiation patch, fed with 50[Formula: see text][Formula: see text] microstrip line and a partial ground plane. The partial ground plane is the combination of shapes of rectangle and three-point arc. The proposed antenna is simulated as well as fabricated. The simulated results using electromagnetic solver software and measured with vector network analyzer bench MS46322A are presented and compared. The various parameters such as return loss, voltage standing wave ratio (VSWR), antenna impedance, gain, directivity, group delay and phase of [Formula: see text], radiation efficiency and patterns are presented here. The depth of return loss is improved for a wide range of frequencies. The proposed fractal antenna is further extended to linear array to improve the gain and impedance bandwidth. The simulated and measured results prove the superiority of the proposed antenna.

Analyzing the Performance of an Inset Fed Sierpinski’s Carpet Rectangular Microstrip Fractal Antenna

are needs of wireless communication systems in modern society. The required systems should have wider bandwidth, low profile multiband and several applications. The researchers have initiated research in number of directions. New approaches and recent researches can be made for the study of fractal shaped antenna elements. Traditional antennas operate at single or dual frequency bands and different antenna is required for different applications. In this paper, the Sierpinski's carpet microstrip fractal antenna is considered. The behaviour of Sierpinski's antenna related to the design procedure, numerical simulation using methods of moments, importance of IE3D softwere to simulate this antenna are investigated.

A New Triple Band Microstrip Fractal Antenna for C-band and S-band Applications

Recently research show that some parameters such as the shapes of antenna patch and the ground plane when geometrically altered produces changes in the current density distribution of the planar structure and consequently in the resonant modes. This paper presents a new microstrip fractal antenna using the technique of inserting slots of shape fractal in ground plane in order to increase the bandwidth and insertion discontinuities in the feed line to reach specific behaviors in three resonant modes. The FR-4 substrate with dimensions 85.0 x 85.0 x 1.57 mm3 is used. Also, it used different techniques of impedance matching in feed line of antenna with changes of the width of the transmission line in order to obtain a variation in the current distribution and consequently of the impedance bandwidth for S11 ≤ -10dB for C-band (3.625 GHz – 4.2 GHz) and S-band (2.0 GHz – 4.0 GHz). Good agreement between measured and simulated results is achieved. Proposed fractal microstrip antenna can be easily designed, built and applied in wireless communication.

‘X’ Shape Slot based Microstrip Fractal Antenna for IEEE 802.11 WLAN

‘X’ Shape Slot based Microstrip Fractal Antenna for IEEE 802.11 WLAN

SierpinskiArray with Swastik Electromagnetic Bandgap for Ku-Band Applications

Objectives: Novel and miniaturized array with four elements is designed in this paper. To make it applicable for multiband applications the array elements are fractured. Improvement in terms of its performance parameters like gain and bandwidth is done by introducing Electromagnetic Bandgap (EBG) structure. The antenna is applicable for satellite applications. Methods/Analysis: A four element array using Right Isosceles Triangular Microstrip patch Antenna (RITMA) is designed first. Further two iterations are done based on Sierpinski fractal geometry. Swastik shape electromagnetic bandgap (EBG) is then introduced into the substrate. The antennas have been modeled and optimized by using the CST Microwave Studio tool. The antennas have been designed using Rogers RT 5880 substrate (e r = 2.2) and a substrate height of 2.5 mm and compared with FR-4 (e r = 4.4) and a substrate height of 1.59 mm.Comparison is also been done with structures having EBG structures and without EBG. Both antennas have been designed using inset feed. It has been found that array with EBG exhibits better results as compared with without EBG. Findings: New Microstrip fractal patch antenna planar array with and without swastika shape EBG structure is been proposed. The antenna works in multiband where its resonances are at 7.9, 9.7, 12.0, 14.1, 16.2, and 18.5 GHz within 7-19 GHz. Bandwidth obtained is 165.7, 186.8, 444, 450, 549, 594 MHz, and Gain 7.39, 10.96, 7.39, 9.73, 10.14, 9.21dB respectively at these resonances. Both antennas shows multiband behavior but area used is less in EBG structure. Novelty/Improvement: In this paper, an approach for multi-band antennas is proposed. First an RITMA array with four elements is designed. It is then fractured using Sierpinski fractal, on the substrate EBG structure is added to get better results. The antenna shows compact dimensions with good return loss and pattern performance to be adopted for satellite applications.

A Chaucer microstrip fractal antenna for mobile applications

In this paper a Chaucer fractal patch antenna integrated with split ring structure is simulated using Ansoft’s (HFSS), as well as fabricated and tested using VNA. The obtained results indicate that the proposed antenna resonates at 2.4 GHz in the ISM band. In addition, the structure offers multi-band operation with the fair value of return loss, gain, and bandwidth, impedance and directivity in the entire range of frequency operation.