Conventional Rectangular Patch Research Articles

A novel miniaturized metamaterial inspired frequency reconfigurable antenna with switchable polarization for sub 6 GHz band

Abstract A metamaterial-inspired frequency reconfigurable antenna with switchable polarization realized for 2.4 GHz, 3.5 GHz, and 5.8 GHz frequencies, is reported in this work. Initially, a conventional rectangular patch is designed to resonate at 3.5 GHz. A regular square-shaped SRR (Split Ring Resonator) is a metamaterial-inspired structure that excites additional resonance at 5.8 GHz, without increasing the antenna form factor. Further, a parasitic patch is introduced to create one resonance at 2.4 GHz. Reconfigurability of frequency and polarization is achieved using MPP4203 series PIN diodes. The antenna is simulated using CST Microwave Studio Suite 2019. The designed antenna, characterized by reflection coefficient and bandwidth is analysed for three diode states. The devised antenna operates at 2.4 GHz, 3.5 GHz, and 5.8 GHz, with a maximum bandwidth of 346.2 MHz at the 5.8 GHz frequency band. The radiator outperformed other similar antennas reported in the literature in terms of antenna size, bandwidth, and frequency cum polarization reconfigurability.

Symmetric CRLH-TL filter based dual band microstrip antenna design approach

This paper presents a novel filter-based analysis for the conventional rectangular patch antenna (RPA) using the Composite Right/Left-Handed Transmission Line (CRLH-TL) theory. We introduce two circuit models for RPA, described by lumped components and transmission line (TL) elements. An RPA is considered a Symmetric CRLH-TL (SCRLH-TL). We validated the analysis by comparing the circuit model and full-wave analysis simulation results. The TL circuit model error in the full-wave analysis was less than 5%. A dual-band Zeroth-Order Resonant (ZOR) antenna is designed and manufactured based on the introduced Lumped element circuit model, which exhibits filtering characteristics in both bands. We obtain the antenna circuit model by incorporating the RPA lump circuit model with LC resonators. We implemented the antenna structure by combining the RPA and complementary split-ring resonators (CSRR) modeled by the LC resonators. We initialized the antenna center frequency bands for WiMAX 2.45 GHz and 3.60 GHz. The CSRRs control the configuration of the center frequencies. The simulation and measured results are in good agreement. The proposed antenna dimensions are 0.66×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document}0.66×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document}0.012 λg\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\lambda _g$$\\end{document} at 2.45 GHz (43.22×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document}43.22×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document}0.81 mm3). The measured gains are 3.47 dB and 4.64 dB for 2.45 GHz and 3.60 GHz, respectively. Two radiation nulls were observed at 2.09 GHz and 2.98 GHz for the 2.45 GHz band and one radiation null at 3.45 GHz for the 3.60 GHz band. Also, the fractional bandwidth is 4.03% and 1.39%, respectively. The radiation pattern is nearly omnidirectional. The simulated efficiency is 90% for 2.45 GHz and 87% for 3.60 GHz frequency bands.

Mobile-integrated SRR-based four-port MIMO antenna for broadband mm-wave 5G applications

ABSTRACT A low-profile, single-layered, compact-size, highly-isolated four-port MIMO antenna integrated within a 5 G smartphone has been proposed for a futuristic mm-wave broadband communication system. The proposed MIMO antenna configuration has been derived from a conventional inset-fed rectangular microstrip patch by introducing two parallel I-shaped slots on the patch surface for operating over a wide bandwidth of 4.91 GHz, that is, from 26.78 to 31.69 GHz. The antenna geometry has an overall dimension of 20.9 mm x 20.9 mm x 0.787 mm. The proposed configuration attained a maximum gain of 8.11 dBi and radiation efficiency of 90% at 28 GHz resonating frequency. The integration of the square-shaped SRR structure among closely packed antenna elements has significantly enhanced the overall isolation by 13 dB without compromising the antenna’s physical dimensions. The realisation of the S-parameters has also been carried out from the equivalent circuit model to agree with the results obtained from the electromagnetic simulation through CST software. The measured radiation patterns assured the minimal variation with simulated characteristics along the E and H planes. A comprehensive safety investigation of the proposed MIMO antenna has been carried out to assess power densities (<10 W/ m 2 ) across different usage modes, including data, reading, and talking in a mobile application perspective. Several diversity parameters, including ECC (<0.0001), DG (>9.999 dB), CCL (<0.12 bits/sec/Hz), MEG, and TARC, have also been evaluated as performance metrics. Furthermore, the linear transmission property of the proposed MIMO antenna has been validated through the variation of group delay (<0.5 ns) over operating frequency bands in the far-field region.

Slot-loaded Dual-Band Microstrip Patch Antenna for 5G and WLAN/WiMAX Wireless Applications

Objectives: This study introduces a dual-band rectangular microstrip patch antenna with a slot-loaded, specifically designed for 5G and WLAN/WiMAX applications. Method: The antenna is mounted on a substrate material of Rogers AD255C material having εr of 2.55 and a thickness of 1.56 mm. Three slots are etched on the conventional rectangular microstrip patch antenna. A 50-ohm microstrip line powers the antenna. The antenna that has been suggested is created and simulated using CST Studio Suite 2020. Findings: Based on numerical simulation, the proposed antenna functions at 3.5 GHz and 5.8 GHz, suitable for 5G and WLAN/WiMAX wireless technologies. The antenna offers measured return loss (S11) of -22.10 dB and -22.9 dB and a Gain of 4.43 dBi and 4.62 dBi at 3.5 GHz and 5.8 GHz, respectively. The radiation patterns are linear and broadside. Novelty: This article aims to create a smaller planer dual-band antenna that integrates WLAN/WiMAX and 5G communication standards into a single device. Keywords: Dual-band, 5G, WLAN, WiMAX, Microstrip patch antenna

Design of a Compact Wearable Antenna for IoT Enabled Bio-Telemetry in Diagnostic Health Monitoring System

The structure developed involves the etching of Moore’s curve onto a conventional rectangular patch and subsequently encasing it in a rectangular loop along with a defected ground structure. The proposed antenna exhibits dual-band Since the Internet of Things (IoT) enabled medical diagnostic system requires unprecedented precision and automation for better health care delivery, therefore in such systems, the performance of antennas for efficiently transferring data (vital functions of the human body) is an important task. To address these concerns, a mechanically robust, novel hybrid wearable on-body antenna inspired by Moore’s fractal based geometry and conventional rectangular loop for a diagnostic health monitoring system is proposed. with bandwidth ranging from 1.38 - 1.8 GHz and 2.25 - 4.88 GHz respectively, covering WMTS, ISM, and Personal Communication band besides covering a portion of UWB band also. The two operating bands of the antenna offer a fractional bandwidth of 38.5% and 73.7% respectively. It is observed that the average specific absorption rate (SAR) over the multi-layer phantom is 0.025 W/kg for an input power of ≈ 24 dBm. In comparison to the recently reported wearable antennas, the design proposed has a compact footprint of 0.135 λo x 0.093λo x 0.004λo besides offering a dual- band of operation, peak gain of 2.2 dBi, overall radiated efficiency of 95% and SAR below 0.025 W/kg. The design is fabricated using Rogers 5880 substrate (semi-flex) of thickness 0.75 mm.

A Dual-Band Low SAR Microstrip Patch Antenna with Jean Substrate for WBAN Applications

This paper presents a low-profile dual-band microstrip patch antenna operated at the 2.45/5.8 GHz ISM bands, targeting wireless body area network (WBAN) applications. The proposed antenna is fabricated on a jean substrate measuring 74×82 mm2. The four corners of the conventional rectangular patch are cut to activate an additional operating frequency and to enhance the radiation pattern. The circular slot is added to the radiating patch to fine-tune the desired frequencies. The measured impedance bandwidth of the proposed antenna at 2.45 GHz and 5.8 GHz bands is 3.68% (2.40 GHz–2.49 GHz) and 3.81% (5.67 GHz–5.89 GHz), respectively. The measured maximum gains are 3.08 dBi at 2.45 GHz and 2.15 dBi at 5.8 GHz. Moreover, the antenna’s performance when placed on flat and rounded body surfaces is also investigated. The proposed antenna achieves stable radiation pattern and low specific absorption rate (SAR) value with low complexity in design. The results indicate that the proposed antenna can be a promising candidate for WBAN applications.

Design and analysis of frequency selective surface embedded broadband high gain miniaturized antenna

SummaryIncorporating the better impedance matching capability of planar curved radiating patch, a miniaturized broadband planar antenna has been designed, analyzed, and integrated with frequency selective surface (FSS) to accomplish higher gain for various short‐range and long‐range modern wireless communication applications. Physical and electrical volume of the presented antenna is 25 × 20 × 1.6 and 0.25 × 0.20 × 0.016, respectively. The proposed radiating patch is constructed from a conventional rectangular patch by transforming the upper side of the patch into a semi‐circular shape and the lower side of the patch into a staircase‐like shape. Measured outcomes of the designed antenna show a very large operating bandwidth of 19.8 GHz (3–22.8 GHz) with a fractional bandwidth (FBW) of 153.5% and bandwidth dimension ratio (BDR) of 3070. An equivalent circuit model (ECM) of the proposed antenna is developed using an advanced design system (ADS) circuit simulator. The frequency responses of the ECM are compared with the simulation done by CST Microwave Studio Suite software and measurement results, which show good agreement. An FSS structure with stop band from 2–28 GHz is positioned beneath the proposed antenna at optimal position (27 mm below the antenna) to enhance the gain up to 8.9 dBi. The presented antenna and FSS are fabricated on FR4 substrate and experimentally verified using standard microwave measurement setup.

Simple Integration of Cavity-Backed Antenna with Patch Antenna for Developing Hybrid Antenna Using SIW Technology

This paper proposes a novel scheme for developing a linearly polarized (LP) hybrid antenna using a simple integration of a planner cavity-backed antenna with a conventional rectangular patch antenna. To substantiate, a half-mode rectangular substrate-integrated waveguide technique is divided into halves to reduce the size and later integrated with a patch antenna. The patch antenna is getting excited by the mutual coupling of TE101 mode and resonating in the vicinity of the cavity resonator. These two different combinations of strategy let the antenna obtain superior characteristics such as bandwidth and gain. To make this structure enable to use in the planner circuit, a 50 Ω microstrip line is incorporated. This proposed hybrid antenna is simulated and tested experimentally to justify its worthiness. The simulated and measured data maintained good agreements regarding S11, bandwidth, gain, radiation pattern, and efficiency.

Design of folded rectangular microstrip antenna on thinner substrate for wideband response

ABSTRACT Wideband microstrip antenna is realized by adding more than one resonant modes in the patch. In this paper, on electrically thinner substrate, design of modified shape rectangular microstrip antenna by employing folded rectangular patch is presented for linear polarized wideband response. Unlike the conventional rectangular patch, radiation pattern and resonance frequency at the second-order resonant mode are modified and along with the fundamental mode, yield wider bandwidth. On substrate of thickness 0.045λ0, folded patch design yields bandwidth of more than 20% along with the broadside radiation pattern and gain more than 8 dBi. Against the reported wideband designs, proposed design does not employ parasitic patches, resonant slot, modified ground plane structures, but on thinner substrate achieves the bandwidth of more than 20%. Resonant length formulation and subsequent design methodology are presented, which is useful in realizing similar folded antenna as per the specific frequency band. Simulated results have been experimentally verified, which shows close agreement.

Design and Assessment of Bio-Inspired Antennas for Mobile Communication Systems

RF front-end system in the mobile communication system consists of an antenna, filter, and amplifier section. Now a day, there is a need to reduce the size of this RF front-end system. Here the challenge is the reduction in the size of the RF front end without degrading the performance. One way to reduce the size is by reducing the size or area of the antenna. This work proposes and simulates three Bio-inspired microstrip (BIMS) antenna designs. They are flower, Butterfly, and leaf shapes presented based on the perturbation method, Gielis super formula, and modified polar transformation models, respectively. These BIMS antennas were printed on fiberglass laminate (FR4) as substrate with a dielectric constant of εr = 4.4 and a loss tangent of 0.02. The simulation results cover parameters of the antenna, such as reflection coefficients (S11), surface current density (Jsurf), and radiation patterns. They offer a maximum gain of 14 dBi, 8 dBi, and 4dBi, respectively, and their results are compared with other works. These antennas are less in size, so they occupy less area compared to conventional rectangular or circular patch antenna, which radiates in L and S bands at different frequency ranges.

Dual polarization and mutual coupling improvement of UWB MIMO antenna with cross shape decoupling structure

A simple, compact MIMO antenna that operates in the UWB frequency band is presented in this paper. The proposed antenna consists of four elements where the shape of the radiators derived from series modifications of a conventional rectangular patch antenna. Radiators are placed orthogonally to each other to achieve the dual polarization operation and cross shape Defected Ground Structure (DGS) is inserted in the ground plane to improve decoupling between the antenna elements. The designed model was fabricated on FR-4 substrate with dimensions of 48 × 44 × 1.6 mm3 and measurements were performed to validate the simulated results. The fractional bandwidth reaches 112% from 3.1 GHz to 11 GHz with reflection coefficient less than -10 dB and mutual coupling between antenna elements is less than -20 dB. The antenna has a stable radiation pattern, and low gain variation. In addition, the time domain characteristics and diversity performance indicators were evaluated and compared with the standard values. The miniaturized dimensioning of the antenna along with the good performance metrics indicates that the proposed antenna can be used in various UWB applications such as portable handheld devices.

A miniaturized rectangular microstrip patch antenna with negative permeability unit cell metamaterial for the band 2.45 GHz

This work presents a miniaturized rectangular patch Antenna with negative permeability metamaterial unit cell etched on the ground plane of a conventional patch antenna operating at 3.3 GHz. The new compact metamaterial (MTM) antenna is resonating at 2.45 GHz. It is 44,82% smaller than a conventional rectangular patch antenna resonating at 2.45 GHz and has a bandwidth of 183.3 MHz, a reflection coefficient of -45,36 dB and a gain of 1.37dB, the materials used for the conception are FR-4 dielectric as a substrate, its permittivity is 4.4 and cooper annulled as metal for radiating element and the ground plan, the simulation of the antenna was done with CST solver.

Design of Broadband Aperture-Coupled Stacked Microstrip Antennas Using Second-Order Filter Theory

In this article, the authors propose a lumped circuit methodology for the design of broadband stacked microstrip patch antennas fed through an aperture. First, an equivalent circuit (EC) is introduced for the antenna. The EC consists of an <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$LC$ </tex-math></inline-formula> series resonator modeling the feed plus two capacitively coupled <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$LC$ </tex-math></inline-formula> parallel resonators accounting for the radiating patches. Then, a deembedding procedure based on total least squares method is introduced to determine all the parameters of the antenna EC. Second, the circuit stage modeling the patches is designed as a second-order Chebyshev filter based on coupled resonators. Since the standard Chebyshev approach leads to circuit parameters that cannot be physically obtained in practice, a modified second-order quasi-Chebyshev design is presented, which can be physically implemented by stacking one conventional rectangular patch above one rectangular patch with both inner and meandering slots. The proposed methodology is used to design an antenna with over 30% bandwidth at a center frequency of 5.57 GHz. A prototype has been fabricated and measured, and good agreement has been found between simulations and experiments.

High gain miniaturrized super‐wideband microstrip patch antenna

SummaryA miniaturized super‐wideband (SWB) monopole antenna is presented in this work. Electrical dimension of the presented antenna is 0.239λ × 0.239λ × 0.0147λ, where λ indicates the wavelength corresponding to the lowest operating frequency. Presented antenna displays single −10 dB operating band from 2.75 to 28 GHz with 164% percentage bandwidth and bandwidth ratio of more than 10:1. The proposed SWB antenna exhibits a large bandwidth dimension ratio (BDR) of 2871 with realized gain of 4.80 dBi. Radiating patch of the proposed antenna is designed by modifying conventional rectangular patch by loading a matching stepwise structure. Further, in order to achieve SWB characteristics, the ground plane is reduced with a loaded rectangular notch for better impedance matching. The designed antenna has the advantages of simple planar miniaturized structure, acceptable gain, and wide bandwidth to support various objectives in modern wireless communication. To boost the maximum gain further over the entire frequency band, the proposed antenna is combined with the proposed frequency selective surface (FSS) which acts as a partially reflector surface. The antenna is placed over 4 × 4 FSS at suitable distance without hampering the obtained bandwidth of the antenna. FSS combined antenna structure, having the physical volume of 56 mm × 56 mm × 26.2 mm, exhibits realized gain of 9.3 dBi which is suitable for long range communication. CST MWS (Microwave studio) for simulation results of the suggested antenna and appropriate Microwave Test bench is used to verify the same.

Design and Bending Analysis of Wearable Compact Patch Antenna for Medical Telemetry Based on Flexible Material

A comprehensive study of compact flexible patch antenna, which is the suitable topology for medical telemetry operated in the industrial scientific and medical (ISM) band, is presented. For establishing efficient wireless links for assisting medical diagnostics, the antenna is required to be of a low profile, safe, and simple geometry. To achieve the compactness of the structure, Taguchi’s optimization method has been applied based on the concept of orthogonal array. The designed antenna uses two distinct flexible substrates, namely polyethylene terephthalate (PET) with dimension 43.5x36.89x0.175 mm3, and Rogers RT/Duroid 5880 with dimension 48.5x49.66x1.58 mm3 categorized under materials, namely plastic and circuit (microfiber reinforced PTFE) material respectively. The approach has been demonstrated for a simple, compact flexible antenna with reduced dimension by 5.37% for PET, and 23.96% for RT 5880 as compared to the conventional rectangular patch design parameters. The resonant frequencies of the designed antennas are 2.435 GHz and 2.45 GHz for PET, and Rogers RT/Duroid 5880, respectively, with a bandwidth of 73.2MHz for RT/Duroid, and 16.8 MHz for PET. The maximum observed directivity of the proposed antenna using PET and Rogers RT/Duroid 5880 are 5.15 dBi, and 6.117 dBi, respectively, at 2.45 GHz. Furthermore, characterization for performance variation is carried out through bending analysis for different curvatures and Specific Absorption Rate (SAR) analysis in order to demonstrate its suitability for direct integration with wearable biomedical sensing chips used for medical telemetry.

Three‐dimensional miniaturized super wideband antenna with filtering capabilities

This article presents a miniaturized three-dimensional super wideband antenna with filtering capabilities. A conventional rectangular patch antenna has been modified by truncating its corners with semi-circles and a trapezoidal shaped partial ground plane is utilized to achieve super wideband performance. The planar design is later extended to a 3D design with the addition of three dielectric cuboids in the radiator. The cuboids are inserted at low current density regions within the operating range to achieve miniaturization compared to the planar antenna. The impedance bandwidth of the 3D antenna is ~17.55 GHz, measured from 2.45 to 20 GHz. The filtering capabilities are achieved by means of an upside-down T-shaped resonator introduced in the center of the patch and two U-shaped slots etched from the patch. In total, three interfering communication bands are rejected, WiMAX (3.2–3.8 GHz), IEEE 802.11/WLAN (5.17–5.33 GHz), and ITU (7.7–8.5 GHz). The proposed antenna is miniaturized as it merely has an overall size of 0.20λl × 0.19λw × 0.011λh mm3 (corresponds to 2.45 GHz) compared to the relevant literature. The design has been analyzed using an equivalent circuit model, fabricated and measured for validation. The simulated and measured results are found well in agreement.

Bandwidth enhancement of dual-band bi-directional microstrip antenna using complementary split ring resonator with defected structure for 3/5 GHz applications

&lt;span&gt;This paper presents a bandwidth enhancement of a dual-band bi-directional rectangular microstrip patch antenna. The novelty of this work lies in the modification of conventional rectangular microstip patch antenna by using the combination of two techniques: a complementary split ring resonator (CSRR) and a defected patch structure (DPS). The structure of antenna was studied and investigated via computer &lt;/span&gt;&lt;span&gt;simulation technology (CST). The dimension and position of CSRR on the ground plane was optimized to achieve dual bandwidth and bi-directional radiation pattern characteristics. In addition, the bandwidths were enhanced by defecting suitable shape incorporated in the microstrip patch. A prototype with overall dimension of 70.45×63.73 mm&lt;sup&gt;2&lt;/sup&gt; has been fabricated on FR-4 substrate. To verify the proposed design, the impedance bandwidth, gain, and radiation patterns were carried out in measurements. The measured impedance bandwidths were respectively 560 MHz (3.08-3.64 GHz) and 950 GHz (4.64-5.59 GHz) while the measured gains of each bandwidth were respectively 4.28 dBi and 4.63 dBi. The measured radiation patterns were in good agreement with simulated ones. The proposed antenna achieves wide dual bandwidth and bi-directional radiation patterns performances. Consequently, it is a promising candidate for Wi-Fi or 5G communications in specific areas such as tunnel, corridor, or transit and rail.&lt;/span&gt;

Design of a Compact Hybrid Moore’s Fractal Inspired Wearable Antenna for IoT Enabled Bio-Telemetry in Diagnostic Health Monitoring System

Since the Internet of Things (IoT) enabled medical diagnostic system requires unprecedented precision and automation for better health care delivery, therefore in such systems, the performance of antennas for efficiently transferring data (vital functions of the human body) is an important task. To address these concerns, a mechanically robust, novel hybrid wearable on-body antenna inspired by Moore’s fractal-based geometry and conventional rectangular loop for a diagnostic health monitoring system is proposed. The structure developed involves the etching of Moore’s curve onto a conventional rectangular patch and subsequently encasing it in a rectangular loop along with a defected ground structure. The proposed antenna exhibits dual-band with bandwidth ranging from 1.38 - 1.8 GHz and 2.25 - 4.88 GHz respectively, covering WMTS, ISM, and Personal Communication band besides covering a portion of UWB band also. The two operating bands of the antenna are wideband with fractional bandwidth of 38.5% and 73% respectively. It is observed that the average specific absorption rate (SAR) over the multi-layer phantom is 0.025 W/kg for an input power of ≈ 24 dBm. In comparison to the recently reported wearable antennas, the design proposed has a compact footprint of 0.135 λo x 0.093λo x 0.004λo besides offering a dual- band of operation, peak gain of 2.2 dBi, overall radiated efficiency of 95% and SAR below 0.025 W/kg. The design is fabricated using Rogers 5880 substrate (semi-flex) of thickness 0.75 mm. The experimental results validate the simulated results making the proposed antenna a promising candidate for the bio-medical application. On analysing the performance of the proposed antenna onto the human body (human body loading), it is concluded that the proposed antenna structure is appropriate for bio-telemetric application in diagnostic health monitoring systems wherein data is relayed from all bio-sensors to remote control systems.

Giuseppe peano fractal loaded multiband antenna using parasitic strips for THz applications

Multi - functional antennas are desired for future wireless applications like medical imaging, cancer detection, sensing, explosive detection, weather monitoring, automotive and industrial applications etc. In this paper, Multi band terahertz (THz) antenna is integrated on micro device Rogers RT / Duroid 6010 dielectric material having 5 µm thickness and is designed biasing on very thin graphene layer acts as radiating element having thickness of 0.5 µm. Giuseppe peano fractal (GPF) loaded on conventional rectangular microstrip patch in addition of two parasitic strips is simulated using Ansys High frequency structure simulator (HFSS) for multiband applications. This antenna attributes with compact dimensions of 20 µm × 20 µm and resonates with six bands at 3.58 THz, 5.86 THz, 6.28 THz, 6.64 THz, 7.45 THz and 7.96 THz. Designed antenna attains impedance bandwidth (IBW) of 80 GHz (3.53 – 3.61 THz), 80 GHz (5.81 – 5.89THz), 50 GHz (6.25 – 6.30 THz), 170 GHz (6.57 – 6.74 THz), 80 GHz (7.43 – 7.51 THz) and 170 GHz (7.88 – 8.05 THz) with small bandwidth ratio’s (BR) of 1.022, 1.013, 1.008, 1.025, 1.010 and 1.021 at resonant bands respectively. Radiation efficiency (η) at corresponding resonant frequencies are 90.16 %, 88.80 %, 87.25 %, 94.14 %, 83.87 % and 93.73 %. The electromagnetic characteristics such as reflection coefficient (S11), bandwidth (BW), voltage standing wave ratio (VSWR), group delay (td), input impedance (Zin), radiation patterns, gain (G) and radiation efficiency (η) are appraised in this paper.

Investigation of flexible pavement maintenance patching factors using a finite element model

Patching of flexible pavements is one of the most important functions of pavement maintenance. Although finite element modeling has become commonplace in the world of pavement engineering, modeling has not yet been significantly leveraged for maintenance applications which improve safety, ride quality, and pavement service life. The objective of this study was to model viscoelastic properties of pavement and patching materials to determine the effect of various repair factors on pavement performance using the finite element method. Specifically, surface permanent deformation, local shear stress concentration, and horizontal strain distribution were investigated. Two types of models were simulated; the first model applied static loading to a surface layer fixed on a plate and the second model applied cyclic traffic loading to a two-layered flexible pavement system. The results demonstrate the importance of patching using a semi-permanent method. The results also demonstrated the accumulated effect of repeated loading using a time-dependent material response. Results also indicated that a larger patching area resulted in less influence of the shape of the area, while a circular area proved superior to a conventional rectangular patch for sizes near the tire footprint and smaller than it. Different responses were observed depending on the type of patching material modeled, demonstrating the effect of material choice in maintenance applications. Finally, mesh optimization was performed to ensure appropriate mesh sizes are used in future studies to accurately represent the pavement layers and patches.