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  • Evaluation the performance of the tin (IV) oxide (SnO2) in the removal of sulfur compounds via oxidative-extractive desulfurization process for production an eco-friendly fuel

    Humadi, J.I.; Issa, Y.S.; Aqar, D.Y.; Ahmed, M.A.; Ali Alak, H.H.; Mujtaba, Iqbal M. (2022)
    Catalysts play a vital role in petroleum and chemical reactions. Intensified concerns for cleaner air with strict environmental regulations on sulfur content in addition to meet economic requirements have generated significant interests for the development of more efficient and innovative oxidative catalysts recently. In this study, a novel homemade nano catalyst (manganese oxide (MnO2) over tin (IV) oxide (SnO2)) was used for the first time as an effective catalyst in removing dibenzothiophene (DBT) from kerosene fuel using hydrogen peroxide (H2O2) as oxidant in catalytic oxidative-extractive desulfurization process (OEDS). The catalyst was prepared by impregnation method with various amount of MnO2 loaded on SnO2. The oxidation step was carried out at different operating parameters such as reaction temperature and reaction time in batch reactor. The extractive desulfurization step was performed by using acetonitrile as solvent under several operating conditions (agitation speed and mixing time). The activity of MnO2/SnO2 catalyst in removing various sulfur compounds from kerosene fuel at the best operating conditions was investigated in this work. The results of the catalyst characterization proved that a high dispersion of MnO2 over the SnO2 was obtained. The experiments showed that the highest DBT and various sulfur compounds removal efficiency from kerosene fuel under the best operating conditions (oxidation: 5% MnO2/SnO2, reaction temperature of 75 0C, and reaction time of 100 min, extraction: acetonitrile, agitation speed of 900 rpm, and mixing time of 30 min) via the catalytic oxidative-extractive desulfurization process was 92.4% and 91.2%, respectively. Also, the MnO2/SnO2 catalyst activity was studied after six consecutive oxidation cycles at the best operating conditions, and the catalyst prove satisfactory stability in terms of sulfur compounds removal. After that, the spent catalyst were regenerated by utilizing different solvents (methanol, ethanol and iso-octane), and the experimental data explained that iso-octane achieved highest regeneration efficiency.
  • Eight-Element Antenna Array with Improved Radiation Performances for 5G Hand-Portable Devices

    Ullah, Atta; Ojaroudi Parchin, Naser; Amar, Ahmed S.I.; Abd-Alhameed, Raed A. (MDPI, 2022-09-19)
    This study aims to introduce a new phased array design with improved radiation properties for future cellular networks. The procedure of the array design is simple and has been accomplished on a low-cost substrate material while offering several interesting features with high performance. Its schematic involves eight air-filled slot-loop metal-ring elements with a 1 × 8 linear arrangement at the top edge of the 5G smartphone mainboard. Considering the entire board area, the proposed antenna elements occupy an extremely small area. The antenna elements cover the range of 21–23.5 GHz sub-mm-wave 5G bands. Due to the air-filled function in the configurations of the elements, low-loss and high-performance radiation properties are observed. In addition, the fundamental characteristics of the introduced array are insensitive to various types of substrates. Moreover, its radiation properties have been compared with conventional arrays and better results have been observed. The proposed array appears with a simple design, a low complexity profile, and its attractive broad impedance bandwidth, end-fire radiation mode, wide beam steering, high radiation coverage, and stable characteristics meet the needs of 5G applications in future cellular communications. Additionally, the smartphone array design offers sufficient efficiency when it comes to the appearance and integration of the user’s components. Thus, it could be used in 5G hand-portable devices.
  • Evaluation of solar energy powered seawater desalination pro-cesses: A review

    Al-Obaidi, Mudhar A.A.R.; Zubo, R.H.A.; Rashid, F.L.; Dakkama, H.J.; Abd-Alhameed, Raed A.; Mujtaba, Iqbal M. (2022-09-08)
    Solar energy, amongst all renewable energies, has attracted inexhaustible attention all over the world as a supplier of sustainable energy. The energy requirement of major seawater desalination processes such as multistage flash (MSF), multi-effect distillation (MED) and reverse osmosis (RO) are fulfilled by burning fossil fuels, which impact the environment significantly due to the emission of greenhouse gases. The integration of solar energy systems into seawater desalination processes is an attractive and alternative solution to fossil fuels. This study aims to (i) assess the progress of solar energy systems including concentrated solar power (CSP) and photovoltaic (PV) to power both thermal and membrane seawater desalination processes including MSF, MED, and RO and (ii) evaluate the economic considerations and associated challenges with recommendations for further improvements. Thus, several studies on a different combination of seawater desalination processes of solar energy systems are reviewed and analysed concerning specific energy consumption and freshwater production cost. It is observed that although solar energy systems have the potential of reducing carbon footprint significantly, the cost of water production still favours the use of fossil fuels. Further research and development on solar energy systems are required to make their use in desalination economically viable. Alternatively, the carbon tax on the use of fossil fuels may persuade desalination industries to adopt renewable energy such as solar.
  • Spring-mass behavioural adaptations to acute changes in prosthetic blade stiffness during submaximal running in unilateral transtibial prosthesis users

    Barnett, C.T.; De Asha, A.R.; Skervin, T.K.; Buckley, John G.; Foster, R.J. (Elsevier, 2022-10)
    Background: Individuals with lower-limb amputation can use running specific prostheses (RSP) that store and then return elastic energy during stance. However, it is unclear whether varying the stiffness category of the same RSP affects spring-mass behaviour during self-selected, submaximal speed running in individuals with unilateral transtibial amputation. Research question: The current study investigates how varying RSP stiffness affects limb stiffness, running performance, and associated joint kinetics in individuals with a unilateral transtibial amputation. Methods: Kinematic and ground reaction force data were collected from eight males with unilateral transtibial amputation who ran at self-selected submaximal speeds along a 15 m runway in three RSP stiffness conditions; recommended habitual stiffness (HAB) and, following 10-minutes of familiarisation, stiffness categories above (+1) and below (-1) the HAB. Stance-phase centre of mass velocity, contact time, limb stiffness’ and joint/RSP work were computed for each limb across RSP stiffness conditions. Results: With increased RSP stiffness, prosthetic limb stiffness increased, whilst intact limb stiffness decreased slightly (p
  • The Impact of moisture and clay content on the unconfined compressive strength of lime treated highly reactive clays

    Muhmed, A.; Mohamed, Mostafa H.A.; Khan, A. (2022-09)
    This study aims to provide a thorough evaluation for the changes in the microstructure and evolution of strength of highly reactive clays that were treated with 7 % lime over a period of curing time as a function of the mixing moisture content. Three series of testing were carried out on specimens with 100 %, 85 % and 75 % of bentonite content and prepared with different moisture content of 10, 20, 30 and 40 % above the corresponding optimum moisture content. Specimens of 100 % bentonite were treated with 7 % of lime, compacted to achieve a predetermined dry unit weight and cured at temperatures of 20 OC and 40 OC for up to 28 days whereas the specimens with 85 % and 75 % of bentonite content were prepared by the addition of sand and were cured at 20 oC for up to 7 days. Unconfined Compressive Strength tests and Scanning Electron Microscopy were conducted to observe the strength and the microstructural changes resulting from increasing mixing moisture content. California Bearing Ratio and Resilient Modulus were correspondingly determined based on correlations with the Unconfined Compressive Strength. The failure pattern was also studied to better understand the ultimate behaviour of lime stabilised clays. The results revealed that the strength of treated bentonite increased with the increase in the moisture content up to 30 % above the corresponding optimum moisture content and with increasing the curing time and temperature. Nevertheless, substituting bentonite with sand on the specimen resulted in a significant reduction on the attained strength. Furthermore, the results of California Bearing Ratio and Resilient Modulus showed that values for both parameters are significantly enhanced with lime treatment. The microstructural analysis provided visual evidence to the improved strength in which the pozzolanic reaction was found to be significantly affected by the amount of moisture in the mixture. The results suggested that compacting lime treated expansive clays with moisture content moderately higher than the optimum moisture content would result in a significant enhancement to the attained strength over the period of curing.
  • Transient liquid phase (TLP) bonding as reaction–controlled diffusion

    Atieh, A.M.; Cooke, Kavian O.; Epstein, M. (Elsevier, 2022-12)
    The transient liquid phase bonding process has long been dealt with as a pure diffusion process at the joint interface, that is, as a mass phenomenon. In spite of the advances in the application of this technique to bond complex engineering alloys, the available models have failed to incorporate the effect of surface phenomena on the joining process. In this work, a new reaction–controlled diffusion formulation model is proposed, and the observation of experimental results of joining Al6061 alloy using thin single (50, 100 micron) and double Cu foils is recorded. This work directly unveils the unique role played by surface reaction–controlled diffusion rather than purely mass diffusion bonding process. Our experimental and modeling results reveal a conceptually new understanding that may well explain the joint formation in TLP bonding process.
  • Fabrication of AA6061/316 composites via a double pin FSP tool

    Liu, S.; Paidar, M.; Mehrez, S.; Ojo, O.O.; Cooke, Kavian O.; Wang, Y. (ScienceDirect, 2022-09)
    In this study, a new double pin tool was utilized for the development of AA6061/316 stainless steel reinforced composite by employing the friction stir processing technique for the first time. The microstructure, hardness, tensile, tribological, and corrosion behaviors of the fabricated composites were investigated and comparative assessments were made with the results obtained from the single-pin tool. The results showed that particle-matrix reaction did not occur in the composites irrespective of the nature of the tool profile. The double-pin tool outstandingly boosted the grain refinement (7.01–5.78 μm), particle fragmentation, and distribution within the Al matrix due to the additional pin-assisted plastic deformation, high straining, dynamic recrystallization, and Zener pinning effects. The double-pin tool improved the microhardness (127–141 HV), tensile strength (162–233 MPa), and corrosion resistance of the composite with respect to the single-pin tool counterparts. The replacement of the single pin tool with a double pin tool diminished the specific wear rate (0.38–0.22 mm3/Nm) of the composite. The double-pin tool has a favourable impact on the structure, mechanical, and corrosion behaviours of the AA6061/316 stainless steel reinforced composite. It is thus recommended for composite development.
  • A Combined Rheological and Thermomechanical Analysis Approach for the Assessment of Pharmaceutical Polymer Blends

    Isreb, Mohammad; Chalkia, Marianiki; Gough, Timothy D.; Forbes, Robert T.; Timmins, P. (MDPI, 2022-08)
    The viscoelastic nature of polymeric formulations utilised in drug products imparts unique thermomechanical attributes during manufacturing and over the shelf life of the product. Nevertheless, it adds to the challenge of understanding the precise mechanistic behaviour of the product at the microscopic and macroscopic level during each step of the process. Current thermomechanical and rheological characterisation techniques are limited to assessing polymer performance to a single phase and are especially hindered when the polymers are undergoing thermomechanical transitions. Since pharmaceutical processing can occur at these transition conditions, this study successfully proposes a thermomechanical characterisation approach combining both mechanical and rheological data to construct a comprehensive profiling of polymeric materials spanning both glassy and rubbery phases. This approach has been used in this study to assess the mechanical and rheological behaviour of heterogenous polymer blends of hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose (HPMC) over a shearing rate range of 0.1–100 s−1 and a temperature range of 30–200 °C. The results indicate that HPC and HPMC do not appear to interact when mixing and that their mixture exhibits the mechanistic properties of the two individual polymers in accordance with their ratio in the mixture. The ability to characterise the behaviour of the polymers and their mixtures before, throughout, and after the glassy to rubbery phase transition by application of the combined techniques provides a unique insight towards a quality-by-design approach to this and other polymer-based solid dosage forms, designed with the potential to accelerate their formulation process through obviating the need for multiple formulation trials.
  • Creative Visualisation Opportunities Workshops: A Case Study in Population Health Management

    Elshehaly, Mai; Sohal, K.; Lawton, T.; Mryant, M.; Mon-Williams, M. (2022-10)
    Population Health Management (PHM) relies on the analysis of data from several sources to account for the complex interaction of factors that contribute to the health and well-being of a population, while considering biases and inequalities across sub-populations. Visualisation is emerging as an essential tool for insight generation from data shared and linked across services including healthcare, education, housing, policing, etc. However, visualisation design is challenged by poor data connectivity and quality, high dimensionality and complexity of real-world routinely collected data, in addition to the heterogeneity of users’ backgrounds and tasks. The Creative Visualisation Opportunities (CVO) framework provides a structured approach for working with diverse communities of visualisation stakeholders and defines a set of participatory activities for the effective elicitation of requirements and visualisation design alternatives. We conducted three workshops, applying variations of the CVO framework, with over one hundred participants from the PHM domain, including clinicians, researchers, government and private sector representatives, and local communities. In this paper, we present the results of preliminary analysis of these activities and report on the perceived impact of visualisation in this domain from a stakeholders’ perspective. We report real-world successes and limitations of applying the framework in different formats (through online and in-person workshops), and reflect on lessons learned for task analysis and visualisation design in the PHM domain.
  • Combining Drone-based Monitoring and Machine Learning for Online Reliability Evaluation of Wind Turbines

    Kabir, Sohag; Aslansefat, K.; Gope, P.; Campean, I. Felician; Papadopoulos, Y. (IEEE, 2022-08)
    The offshore wind energy is increasingly becoming an attractive source of energy due to having lower environmental impact. Effective operation and maintenance that ensures the maximum availability of the energy generation process using offshore facilities and minimal production cost are two key factors to improve the competitiveness of this energy source over other traditional sources of energy. Condition monitoring systems are widely used for health management of offshore wind farms to have improved operation and maintenance. Reliability of the wind farms are increasingly being evaluated to aid in the maintenance process and thereby to improve the availability of the farms. However, much of the reliability analysis is performed offline based on statistical data. In this article, we propose a drone-assisted monitoring based method for online reliability evaluation of wind turbines. A blade system of a wind turbine is used as an illustrative example to demonstrate the proposed approach.
  • Use of ‘wearables’ to assess the Up-on-the-toes test

    Zahid, Sarah A.; Celik, Y.; Godfrey, A.; Buckley, John G. (Elsevier, 2022-10)
    The mechanical output at the ankle provides key contribution to everyday activities, particularly step/stair ascent and descent. Age-related decline in ankle functioning can lead to an increased risk of falls on steps and stairs. The rising up-on-the-toes (UTT) 30-second test (UTT-30) is used in the clinical assessment of ankle muscle strength/function and endurance; the main outcome being how many repetitive UTT movements are completed. This preliminary study describes how inertial measurement units (IMUs) can be used to assess the UTT-30. Twenty adults (26.2 ± 7.7 years) performed a UTT-30 at a comfortable speed, with IMUs attached to the dorsal aspect of each foot. Use of IMUs’ angular velocity signal to detect the peak plantarflexion angular velocity (p-fAngVelpeak) associated with each repeated UTT movement indicated the number of UTT movements attempted by each participant. Any UTT movements that were performed with a p-fAngVelpeak 2SD below the mean were deemed to have not been completed over a sufficiently ‘full’ range. Findings highlight that use of IMUs can provide valid assessment of the UTT 30-second test. Their use detected the same number of attempted UTT movements as that observed by a researcher (average difference, -0.1 CI, -0.2 – 0.1), and on average 97.6 ± 3.1% of these movements were deemed to have been completed ‘fully’. We discuss the limitations of our approach for identifying the movements not completed fully, and how assessing the consistency in the magnitude of the repeated p-fAngVelpeak could be undertaken and what this would indicate about UTT-30 performance.
  • From agro-waste to encapsulated carbon catalyst for improving stability of naphtha desulfurization

    Mohammed, H.R.; Hamad, K.I.; Gheni, S.A.; Aqar, D.Y.; Mahomood, M.A.; Habeeb, O.A.; Ahmed, S.M.R.; Rahmanian, Nejat (2022-10)
    The deactivation of the oxidative desulfurization (ODS) catalysts is a challenge and is a major concern in industrial catalytic processes. In this work, an activated carbon (AC) was prepared from agricultural waste and modified to withstand the ODS activity loss over time. The AC was impregnated with manganese and coated with aluminum oxide to prolong the activity lifetime. The catalysts were characterized by nitrogen adsorption-desorption, scanning electron microscope, energy dispersive X-ray, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and transition electron microscope (TEM). The BET surface areas of the examined AC materials were 814.48 m2/g, 784.76 m2/g, and 755.03 m2/g for the AC, Mn/AC, and coated Mn/AC catalysts, respectively with a dominance of microporous pore size. The TGA showed that the coating layer retards the degradation of the active metal and suppresses phase transitions. XRD showed no change in the structure of the catalyst with a coating layer, and from the TEM analysis, the coating layer thickness was 3.6 nm. The kinetics of the ODS catalysts were investigated. It was shown that the ODS reaction follows the first-order kinetics and is not influenced by the coating layer. The activity decay was also investigated. It is found that the activation energy of the deactivation reaction over the coated catalyst was higher than the uncoated catalyst.
  • Efficient Finite Element Mesh Mapping Using Octree Indexing

    Adalat, Omar; Scrimieri, Daniele (Springer, 2022-09)
    Modern manufacturing involves multiple stages of complex process chains where Finite Element Analysis is frequently used as a simulation method on a discretized mesh to provide an accurate estimation of factors such as stresses, strains, and displacements. The choice of the most suitable element type and density is dependent on the individual manufacturing process or treatment applied at each stage of the process chain. To map between unalike Finite Element meshes, differing in density and/or element type, an Octree spatial index was evaluated as a solution for highly performant mapping. Compared to existing solutions, the Octree spatial index introduces parallelism within index creation and provides a strategy to perform the most complex interpolation technique, Element Shape Function, in a more computationally efficient manner.
  • Model-based generation of manufacturing process plans through incremental topology formation

    Adalat, Omar; Talal, Muhammad; Ali Cherif, Mohammed A.; Scrimieri, Daniele (Springer, 2022-09)
    In advanced manufacturing systems, the production of complex and highly customisable products requires the preparation of many different product specifications and associated manufacturing process plans. The creation of these plans involves the search for the production resources (e.g. robots, machine tools, inspection devices) that are needed to implement the product specifications and how to orchestrate them. We present a model-based approach to the automatic generation of manufacturing process plans from the models of the target products and available resources. The modelling language is based on labelled transition systems, which are useful to represent sequences of operations that can be executed in parallel by multiple production resources. Some preliminary experimental results demonstrate the feasibility of the presented approach.
  • A sustainable integration approach of chlor-alkali industries for the production of PVC and clean fuel hydrogen: prospects and Bangladesh perspectives

    Roy, H.; Barua, S.; Ahmed, T.; Mehnaz, F.; Islam, M.S.; Mujtaba, Iqbal M. (Processes: MDPI, 2022-08)
    The chlor-alkali industries produce caustic soda (NaOH), chlorine (Cl2 ), and hydrogen (H2 ) as primary products. In 2021, the global chlor-alkali market was valued at $63.2 billion. The article evaluates the global aspects of chlor-alkali industries and prospects for Bangladesh. The current production capacity of NaOH from the chlor-alkali industries in Bangladesh is around 282,150 metric tons/year (MT/y). The by-products, chlorine (Cl2 ) of 250,470 MT/y and hydrogen (H2 ) of 7055 MT/y, are produced domestically. The local demand of Cl2 is 68,779 MT/y. However, there are no systematic utilizations of the residual Cl2 and vented H2 , which threatens the sustainability of the chlor-alkali industries. The article prefigures that a 150,000 MT/y PVC plant can utilize 45.2 % of residual Cl2 of chlor-alkali plants, which would be an economical and environmental milestone for Bangladesh. The residual Cl2 can earn revenue of 908 million USD/y, which can be utilized to import ethylene. For the sustainable utilization of vented H2 , production of H2O2 , fuel cell electric vehicle (FCEV) and H2 fuel-cell-based power plant are the feasible solutions. Thus, for the long-term growth of the chlor-alkali industry in Bangladesh and other developing countries, systematic utilization of Cl2 and H2 is the only feasible solution.
  • Manual/digital interactions in 'Project code-named Humpty'

    Johnson, Kate; Evans, Adrian A.; Sparrow, Thomas; Black, L.; Harman, Robert; Yang, D.; Wilson, Andrew S. (Springer Nature, 2022-04)
    ‘Project code-named Humpty’ is a performative art piece involving the creation, fragmentation, and reconstruction of a 2.7 m high classically inspired sculpture. It was conceived to complement an archaeological science research project setting out to explore the use of digital scanning technologies in artefact reconstruction. The statue’s form was free sculpted in clay over a period of four years. It was cast in a self-supporting cementitious material specifically for the purpose of ceremonial fragmentation and subsequent reconstruction by archaeologists. In this chapter, we explore the project’s human/machine intentions, interactions, development processes and their wider implications leading to fragmentation. We explore how 3D terrestrial laser scanning with photogrammetry was used to chart the creation of the sculptural form and how scans informed finite element analysis, essential for safe casting and fragmentation. We show how structured light scanning was essential to create a digital backup of the mould and how drone imagery documented fragmentation tests and 360° imaging recorded studio and quarry activity.
  • Visualising animal hard tissues

    O'Connor, Sonia A.; Sparrow, Thomas; Holland, Andrew D.; Kershaw, Rachael; Brown, Emma L.; Janaway, Robert C.; Ugail, Hassan; Wilson, Andrew S. (Springer Nature, 2022-04)
    This chapter summarises AHRC/EPSRC Science and Heritage Programme-funded research to develop a digital resource to disseminate knowledge of the identification of osseous and keratinous animal hard tissues. The choice of materials in the manufacture of individual artefacts or classes of objects can make a major contribution to understanding their cultural significance and questions of provenance or authenticity. This resource builds on understanding gained through a Fellowship to O’Connor in developing, evaluating and validating identification criteria for these materials in raw, worked and decayed states. The resource concentrates on the non-destructive visual methods of particular relevance to the examination of artworks, historic and archaeological artefacts. The chapter highlights the potential of various visualisation methods and digital technologies to capture and combine 2D images and 3D models and guide the viewer through the multi-scalar visual cues of each material to a reliable identification. By accessing a range of collections, the project has produced a comprehensive and accessible resource, disseminating these findings more widely than could be achieved by a physical reference collection. This resource supports the identification of cultural heritage objects for conservation scientists and heritage professionals and informs the fight against the illegal hunting and trafficking of rare and endangered species.
  • Microwave sensor for liquid mixture identification based on composite right left hand-zero-order resonator for sensitivity improvement

    Hocine, S.; Lashab, M.; Belattar, M.; Ouchtati, S.; See, C.H.; Hu, Yim Fun; Abd-Alhameed, Raed A. (Wiley, 2022)
    This work aims to present an improved version of the liquid mixture identification sensor, the proposed sensor is tested experimentaly on mixture of water ethanol, the identification of liquid is based on the measurement of frequency displacement, and comparison with reference values of water ethanol. This device is based on metamaterial structure which is a CRLH (composite right left hand) resonator with ZOR (Zero Order Resonator). The CRLH in addition to its property of miniaturization effect, when combined with ZOR, the resonant frequency of various volume fraction are extended, which make the sensitivity higher. The high sensitivity of the sensor is obtained by an optimum choice of the CRLH components. The geometrical size of the sensor is 20 mm by 11 mm. It was printed on a RT/Duroid 5880 substrate with a very short testing surface area of 4 mm by 8 mm, the liquid is placed on the top side of the sensor, exactly on the CRLH structure. Three prototypes of sensors operating from 1 GHz to 3 GHz are proposed, designed and simulated using the commercial software HFSS (high-frequency structural simulator). The main advantages of this work is first miaturization effect, second high sensitivity and finaly a wide range of liquid can be tested with this sensor. To prove the working principle, ethanol with different volume fractions was adopted as a liquid under test, the obtained results present very good agreement with the literature and suggested that it is a miniaturised and high sensitive candidate (better than 1.38%) for liquid mixture identification.
  • A Compact Wideband Circularly Polarized Planar Monopole Antenna with Axial Ratio Bandwidth Entirely Encompassing the Antenna Bandwidth

    Alnahwi, F.M.; Al-Yasir, Yasir I.A.; Ali, N.T.; Gharbia, Ibrahim; See, C.H.; Abd-Alhameed, Raed A. (IEEE, 2022-08)
    The antenna presented in this study is a compact wideband monopole with wideband circular polarization that can be used across the whole antenna bandwidth. A rectangular C-shaped patch is partially covered by a ground plane in the proposed planar monopole antenna. Inserting a rectangular stub to the ground plane, etching a slit at the antenna patch, and adding a semicircular stub at the top of the antenna feed line increase the antenna impedance bandwidth (BW) and axial ratio bandwidth (ARBW). An FR4 substrate with overall dimensions of 25 mm×25 mm×1.6 mm is used to create the antenna. The antenna's observed impedance BW is 70% (4.55 GHz in the 4.3-8.85 GHz band), while the measured broadside ARBW is improved to a value of 82.2 percent (5.3 GHz along the range 3.8-9.1 GHz). The impedance BW is perfectly covered by the ARBW; hence the antenna can be considered circularly polarized throughout its operational spectrum. Within the antenna BW, the measured gain is greater than 1.5 dB.

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