scholarly journals A Low-Profile Ultrawideband Antenna Based on Flexible Graphite Films for On-Body Wearable Applications

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4526
Author(s):  
Wenhua Li ◽  
Haoran Zu ◽  
Jinjin Liu ◽  
Bian Wu
Keyword(s):  
Corrosion Resistance ◽  
Horizontal Plane ◽  
Impedance Matching ◽  
Wearable Devices ◽  
Light Weight ◽  
Suitable Candidate ◽  
Wearable Antenna ◽  
Low Profile ◽  
Flexible Graphite ◽  
Good Agreement

This paper presents a low-profile ultrawideband antenna for on-body wearable applications. The proposed antenna is based on highly conductive flexible graphite films (FGF) and polyimide (PI) substrate, which exhibits good benefits such as flexibility, light weight and corrosion resistance compared with traditional materials. By introducing flaring ground and an arrow-shaped slot, better impedance matching is achieved. The wearable antenna achieves a bandwidth of 122% from 0.34 GHz to 1.4 GHz, with a reflection coefficient of less than −10 dB, while exhibiting an omnidirectional pattern in the horizontal plane. To validate the proposed design, the wearable antenna with a profile of ~0.1 mm was fabricated and measured. The measured results are in good agreement with simulated ones, which indicates a suitable candidate for on-body wearable devices.

A low-profile FSS-based high capacity chipless RFID tag for sensing and encoding applications

2021 ◽  
pp. 1-9
Author(s):  
Shahid Habib ◽  
Amjad Ali ◽  
Ghaffer Iqbal Kiani ◽  
Wagma Ayub ◽  
Syed Muzahir Abbas ◽  
...  
Keyword(s):  
Radio Frequency Identification ◽  
High Capacity ◽  
Frequency Selective Surface ◽  
Rfid Tag ◽  
Sensing Applications ◽  
Low Profile ◽  
Simple Geometry ◽  
Chipless Rfid ◽  
Frequency Identification ◽  
Good Agreement

Abstract This paper presents a polarization-independent 11-bit chipless RFID tag based on frequency-selective surface which has been designed for encoding and relative humidity (RH) sensing applications. The 10 exterior U-shaped resonators are used for item encoding whereas Kapton has been incorporated with the interior resonator for RH sensing. This radio-frequency identification (RFID) tag operates in S- and C-frequency bands. The proposed design offers enhanced fractional bandwidth up to 88% with the density of 4.46 bits/cm2. Both single- and dual-layer tags have been investigated. The simulated results are in good agreement with measured results and a comparison with existing literature is presented to show the performance. Simple geometry, high code density, large frequency signature bandwidth, high magnitude bit, high radar cross-section, and angular stability for more than 75° are the unique outcomes of the proposed design. In addition, RH sensing has been achieved by integrating the Kapton on the same RFID tag.

scholarly journals Impedance Enhancement of Textile Grounded Loop Antenna Using High-Impedance Surface (HIS) for Healthcare Applications

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3809
Author(s):  
Mohammed M. Bait-Suwailam ◽  
Isidoro I. Labiano ◽  
Akram Alomainy
Keyword(s):  
Impedance Matching ◽  
Loop Antenna ◽  
Healthcare Applications ◽  
Impédance Surface ◽  
Antenna Structure ◽  
Impedance Surface ◽  
High Impedance ◽  
Low Profile ◽  
Close Proximity ◽  
High Impedance Surface

In this paper, impedance matching enhancement of a grounded wearable low-profile loop antenna is investigated using a high-impedance surface (HIS) structure. The wearable loop antenna along with the HIS structure is maintained low-profile, making it a suitable candidate for healthcare applications. The paper starts with investigating, both numerically and experimentally, the effects of several textile parameters on the performance of the wearable loop antenna. The application of impedance enhancement of wearable grounded loop antenna with HIS structure is then demonstrated. Numerical full-wave simulations are presented and validated with measured results. Unlike the grounded wearable loop antenna alone with its degraded performance, the wearable loop antenna with HIS structure showed better matching performance improvement at the 2.45 GHz-band. The computed overall far-field properties of the wearable loop antenna with HIS structure shows good performance, with a maximum gain of 6.19 dBi. The effects of bending the wearable loop antenna structure with and without HIS structure as well as when in close proximity to a modeled human arm are also investigated, where good performance was achieved for the case of the wearable antenna with the HIS structure.

A Low-Profile Light-Weight Wideband Connected Parallel Slot Array for Wide-Angle Scanning

2020 ◽  
Vol 68 (2) ◽  
pp. 813-823 ◽  
Author(s):  
Yan Li ◽  
Shaoqiu Xiao ◽  
Chang-Hai Hu ◽  
Zhixin Yao
Keyword(s):  
Light Weight ◽  
Wide Angle ◽  
Low Profile

Observation of Cracks of PEEK Polymer Thrust Bearings under Rolling Contact Fatigue in Water

2016 ◽  
Vol 703 ◽  
pp. 172-177 ◽  
Author(s):  
Xiao Chen Shi ◽  
Masaya Orito ◽  
Yuji Kashima ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Corrosion Resistance ◽  
Friction Coefficient ◽  
Cross Sections ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Light Weight ◽  
Low Friction ◽  
High Corrosion Resistance ◽  
Thrust Bearings

Considering the advantages on light weight, low friction coefficient, high corrosion resistance and electric insulation, polymer bearings are widely used under certain environments, where the toughness like metal bearings is not necessary. In our previous study, it was concluded that the main reason for PEEK thrust bearings failure in water was flaking due to surface crack propagation. In the present study, crack observations were made on groove surfaces and cross sections along both radial and rolling directions in order to find the relation between cracks and flaking failures.

scholarly journals Improved Low-Profile Helical Antenna Design for INMARSAT Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Shiqiang Fu ◽  
Yuan Cao ◽  
Yue Zhou ◽  
Shaojun Fang
Keyword(s):  
Pitch Angle ◽  
Satellite Communication ◽  
Design Method ◽  
Impedance Matching ◽  
Axial Ratio ◽  
Antenna Element ◽  
Helical Antenna ◽  
Copper Strip ◽  
Antenna Structure ◽  
Low Profile

A new low-profile variable pitch angle cylindrical helical antenna employing a copper strip as impedance transformer is proposed in this paper. Under the circumstance of a limited antenna height, the circular polarization performance of the antenna has been enhanced by changing the pitch angle and the input impedance matching has been improved by adjusting the copper strip match stub. The design method of the proposed antenna is given. The optimal antenna structure for INMARSAT application has been fabricated and measured. The measured results show that in the whole maritime satellite communication work band the VSWR is less than 1.2, its antenna gain is higher than 9 dBi, and the axial ratio is lower than 2.5 dB. The experimental results have a good agreement with the simulations. The proposed antenna is compact and easy tuning. It provides a promising antenna element for maritime satellite communication applications.

New Developments for the Description of Oil Leakages by Advective Migration From Submarine Pipelines

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Renan Martins Baptista ◽  
Ricardo Antonio Francisco Machado ◽  
Marintho Bastos Quadri ◽  
Ariovaldo Bolzan ◽  
André Lourenço Nogueira ◽  
...  
Keyword(s):  
Horizontal Plane ◽  
Immiscible Displacement ◽  
Preliminary Evaluation ◽  
Leakage Detection ◽  
New Developments ◽  
Gravitational Flow ◽  
The Third ◽  
Alternative Approach ◽  
High Standards ◽  
Good Agreement

The significant growth in offshore operations increases the risk of a pipeline rupture, even considering the high standards of safety involved. Throughout a submarine leakage, four different amounts of oil may be accounted. The first one is the oil volume released until the leakage detection. The second one is the volume leaked throughout mitigation initiatives (e.g., pump shutdown and valve closure). The third parcel is the amount released by gravitational flow. Finally, the fourth and last amount of oil is released due to the water-oil entrainment, generally known as advective migration. Normally, a considerable amount of oil is released in this step. It begins just after the internal pipeline pressure becomes equal to the external one. The present work continues to introduce a mathematical alternative approach, based on the theories of perturbation and unstable immiscible displacement, to accurately estimate the leakage kinetics and the amount of oil released by the advective migration phenomenon. Situations considering different hole sizes and thicknesses were tested experimentally and through simulations. Additional experiments were accomplished using smooth and rough edge surfaces, besides different slopes (using the horizontal plane as reference). Those experiments permitted a preliminary evaluation of the importance of these factors. The results obtained with the model showed good agreement with the experimental data in many situations considered.

scholarly journals Stress Concentration Studies in Flat Plates with Rectangular Cut-Outs Using Finite Element Method

2019 ◽  
Vol 4 (1) ◽  
pp. 66-76 ◽  
Author(s):  
Dheeraj Gunwant
Keyword(s):  
Infinite Plate ◽  
Geometrical Parameters ◽  
Light Weight ◽  
Flat Plates ◽  
Uniaxial Load ◽  
Desirable Feature ◽  
Different Shapes ◽  
Stress States ◽  
Analytical Relations ◽  
Good Agreement

Presence of cut-outs of different shapes is inevitable and is many times considered to be a desirable feature for the design of light-weight components. However, the presence of such cut-outs induces highly localized stresses in their vicinity which cannot be resolved using analytical relations and elementary equations of the strength of materials. In the recent years, FEM has evolved as a crucial tool for handling such problems with reduced degree of complexity. The present investigation is aimed at studying the effect of various geometrical parameters and loading scenarios on the SCF induced in an infinite plate in presence of rectangular cut-out with filleted corners. In the first step, the model was subjected to uniaxial load and the obtained values of SCF exhibited good agreement with analytical values. The model was further subjected to systematically varied stress states and geometrical parameters in order to study their effect on the SCF.

scholarly journals Triple Band Fractal Antenna for Radio Navigation and Fixed Satellite Services using Dragonfly Optimization

2019 ◽  
Vol 8 (3) ◽  
pp. 43-49 ◽  
Author(s):  
A. Kumar ◽  
A. P. S. Pharwaha
Keyword(s):  
Coplanar Waveguide ◽  
Performance Parameter ◽  
Fractal Antenna ◽  
Radio Navigation ◽  
Simulated Performance ◽  
Low Profile ◽  
X Band ◽  
Good Agreement ◽  
Triple Band

This study reports the design of a coplanar waveguide (CPW)-fed triple band fractal antenna for radio navigation and fixed satellite services. Reported antenna has low profile, multiband and wideband performance which make it suitable for the radio navigation and fixed satellite services in S band, C bandand X band. Proposed antenna resonates at 2.6GHz, 4.4GHz, and 8.7 GHz having bandwidth of 0.2457GHz, 0.700GHz, and 4.1980 GHz respectively. Maximumgain for the resonating bands is 3.6 dB, 5.5 dB, and 7.3 dB respectively. Simulated performance parameter of proposed antenna is verified experimentally by testing the fabricated antenna. Measured and simulated results are in good agreement

scholarly journals Circularly polarized rectangular dielectric resonator antenna excited by an off-set conformal metal strip

2019 ◽  
Vol 15 (2) ◽  
pp. 902 ◽  
Author(s):  
U. Illahi ◽  
J. Iqbal ◽  
M. I. Sulaiman ◽  
M Alam ◽  
M. S. Mazliham ◽  
...  
Keyword(s):  
Dielectric Resonator ◽  
Impedance Matching ◽  
Metal Strip ◽  
Antenna Design ◽  
Far Field ◽  
Dielectric Resonator Antenna ◽  
Simulation Techniques ◽  
Resonant Modes ◽  
Rectangular Dielectric Resonator Antenna ◽  
Good Agreement

<p class="Abstract">A rectangular dielectric resonator antenna (DRA) has been excited by an off-set single conformal metal strip. By using such excitation technique two degenerate resonant modes, TExδ11 and TEy1δ1 of the rectangular DRA have been excited to achieve circular polarization (CP). A CP bandwidth of ~ 5.2% in conjunction with a wide impedance matching bandwidth of ~ 54% has been provided by the proposed DRA configuration. The antenna design has been simulated using computer simulation technology (CST). Antenna prototype has been built to verify the impedance matching bandwidth. Far field parameters have been optimized and verified using two simulation techniques in CST i.e. finite integration technique (FIT) and finite element method (FEM). A good agreement between the simulated and measured result has been observed for S11. Similarly a very good resemblance between the far field results from FIT and FEM have been demonstrated.</p>

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