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In this paper, design and realization of a Low Profile Archimedean Spiral Antenna is presented. The Low Profile Archimedean Spiral Antenna is printed on a substrate. The bidirectional radiation patterns of the antenna are converted to unidirectional using uniplanar EBG reflector. This uniplanar EBG ground plane is designed with modification in Compact Uniplanar Photonic Band Gap (UC-PBG) structure. The modified version of UC-PBG ground plane provides much wider bandwidth. This ground plane is tested for its electrical characteristics over the frequency band and used as a reflector with spiral antenna. An Archimedean Spiral antenna is designed and simulated in the frequency band of 0.5–6 GHz. The frequency band of operation for the EBG ground plane/ reflector is of the same order. The physical parameters of the antenna are studied for its electrical characteristics and these parameters are optimized for better electrical characteristics of the antenna. Antenna performance is also compared with conventional Metallic (PEC) reflector. The simulated results are validated with measurement. Comparisons of these results are presented. In this design, the height of the antenna is reduced by 86% compared to conventional cavity backed Spiral Antennas. The bandwidth of proposed EBG cell is 171.4%. For spiral antenna integrated with EBG reflector; the impedance and radiation patterns bandwidth are 169%, on axis axial bandwidth is 169% and off-axis axial ratio bandwidth is 163.6%. [ABSTRACT FROM AUTHOR]

The present study addresses advanced monitoring techniques for particles and airborne molecular contaminants (AMCs) in cleanroom environments, which are crucial for ensuring the integrity of semiconductor manufacturing processes. We focus on quantifying particle levels and a representative AMC, hydrogen chloride (HCl), having known detrimental effects on equipment longevity, product yield, and human health. We have developed a compact laser sensor based on open-path cavity ring-down spectroscopy (CRDS) using a 1742 nm near-infrared diode laser source. The sensor enables the high-sensitivity detection of HCl through absorption by the 2-0 vibrational band with an Allan deviation of 0.15 parts per billion (ppb) over 15 min. For quantifying particle number concentrations, we examine various detection methods based on statistical analyses of Mie scattering-induced ring-down time fluctuations. We find that the ring-down distributions' 3rd and 4th standard moments allow particle detection at densities as low as ~105 m−3 (diameter > 1 μm). These findings provide a basis for the future development of compact cleanroom monitoring instrumentation for wafer-level monitoring for both AMC and particles, including mobile platforms. [ABSTRACT FROM AUTHOR]

Determination of residual stresses in metals, subjected to secondary processing, is necessary from the point of view of their applications and is widely studied in literature. However, residual stresses induced during service is generally ignored when evaluating the performance of the component. The residual stress in a component could be tensile or compressive in nature and eventually affects its service life under external loading. In this regard, industries demand rapid, efficient, and easier methods of non-destructive testing to identify and control the residual stress in such components. The present work aims at evaluation of residual stress in an LM-25 aluminium alloy/fly Ash Metal Matrix Composites (AMC) after subjecting the specimen to dry sliding wear tests. X-ray diffraction technique was used to measure the residual stress in the "pin" specimen of the pin-on-disc set-up. The residual stress was ~ 24 % higher in the composite compared to the un-reinforced alloy after the wear test while the wear rate, measured in terms of weight loss of the pin, was lower by about 50%, under similar test conditions. [ABSTRACT FROM AUTHOR]

Solid state sintering of cast aluminum powders by resistance heating sintering (RHS), also known as spark plasma sintering or field-assisted sintering technique, creates a very fine microstructure in the bulk material. This leads to high performance material properties with an improved strength and ductility compared to conventional production routes of the same alloys. In this study, the mechanical behavior of an RHS-sintered age-hardenable A357 (AlSi7Mg0.6) cast alloy and a SiCp/A357 aluminum matrix composite (AMC) was investigated. Aiming for high strength and good wear behavior in tribological applications, the AMC was reinforced with a high particle content (35 vol.%) of a coarse particle fraction (d50 = 21 µm). Afterwards, separated and combined effects of particle reinforcement and heat treatment were studied under compressive load both at room temperature and at 350 °C. At room temperature compression, the strengthening effect of precipitation hardening was about twice as high as that for the particle reinforcement, despite the high particle content. At elevated temperatures, the compressive deformation behavior was characterized by simultaneously occurring temperature-activated recovery, recrystallisation and precipitation processes. The occurrence and interaction of these processes was significantly affected by the initial material condition. Moreover, a rearrangement of the SiC reinforcement particles was detected after hot deformation. This rearrangement lead to a homogenized dispersion of the reinforcement phase without considerable particle fragmentation, which offers the potential for secondary thermo-mechanical processing of highly reinforced AMCs. [ABSTRACT FROM AUTHOR]

A compact antipodal Vivaldi antenna array (AVAA) with ultra-wideband (UWB) beam steering capabilities is presented. The fabricated and measured array prototype has good matching from about 1.5 GHz to 11 GHz (147%) for all ports and can achieve wide angle steering, with low side-lobe and cross-pol levels, within that range. The compact 118.6 mm $ \times 81$ mm design also has a maximum gain of 13.5 dBi and the 13.6 mm E-Plane element spacing allows the array to be steered across this matching range with no grating lobes present. The AVAA is further enhanced by the introduction of artificial magnetic conductors (AMCs) onto the surface of the array elements themselves to reduce broadside scattering, without increasing aperture size, and this approach is non-conventional. Moreover, the small rectangular AMC cells reduce the scattering from 5.7 to 18.4 GHz (105%) for both horizontal and vertical polarisations and this scattering reduction approach, which is also critical for compact implementations, is verified through measurements as is the absence of any performance degradations caused by these AMC inclusions. Applications of the compact AVAA include imaging, new UWB radar systems, and whenever UWB beamsteering is required with reduced scattering.

This paper presents a new low-area and low-power Field Programmable Gate Array (FPGA) implementation of a Radio Frequency (RF) modulation classifier based on the Density-Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm, known as DBCLASS. The proposed architecture demonstrates a novel approach for the efficient hardware realisation of the DBSCAN algorithm by utilising parallelism, a bespoke sorting algorithm, and eliminating memory access. The design achieves 100% classification accuracy with lab-captured RF data above 8 dB signal-to-noise ratio(SNR) whilst exhibiting an improvement of latency in comparison to the next quickest design by a factor of 7.5, a reduction in terms of total FPGA resources used in comparison to the next smallest complete system by a factor of 3.65, and a reduction in power consumption over the next most efficient by a factor of 4.75. The proposed design is well suited for resource-constrained applications, such as mobile cognitive radios and spectrum monitoring systems.

This communication presents a wideband and a low-profile flexible wearable antenna intended to operate at a 2.45 GHz WBAN band. The suggested antenna comprises a CPW-fed monopole antenna backed by an artificial magnetic conductor (AMC) to act as a reflector. The latest AMC-integrated design uses R03003 as a dielectric substrate. The suggested design features an impedance bandwidth of 71.03% (1.87–3.93 GHz) with a gain value of 3.62 dBi and has a compact footprint of 40 × 40 mm2. The incorporation of wideband AMC with a monopole antenna leads to bandwidth enhancement and covers the 3.5 GHz WiMAX band. Simulation and experimental studies provide evidence that in the case of structural deformities and human body loading, the suggested AMC-integrated antenna is stable and shows superior efficiency relative to the traditional monopole antenna. Furthermore, numerical analysis demonstrates that the amount of radiation AMC-integrated antenna decreases tremendously in terms of specific absorption rate for various bodily attachment scenarios. Three body templates with various compositions and forms were used to study the effects of the antenna on bodily attachment. Extensive experiments on human body phantoms and bodily attachment are also conducted and the results are presented. The suggested AMC-integrated design thus confirms a promising contender for portable wearable wireless applications. [ABSTRACT FROM AUTHOR]

A novel compact antenna with characteristics of broadband and high gain is proposed in this paper. The proposed antenna comprises 1 × 2 elements that are connected together by a balance power divider. To create a new shape, the proposed antenna is a combination of dipole and patch shapes and acts as a monopole. As a result, the impedance bandwidth is enhanced. Additionally, the gain of the proposed antenna is improved by using an artificial magnetic conductor (AMC) surface. The antenna prototype, with an overall size of 0.66 λ0 x 0.79 λ0 x 0.11 λ0 (λ0 is the wavelength in free space at the lowest operating frequency of 2.63 GHz) has a −10 dB bandwidth of 78% (2.63–6 GHz), a broadside gain of 11.5 dBi, 3-dB gain bandwidth of 19%, and a total efficiency over79% in all operating frequency bands. Thanks to the presence of AMC surface and the combination ofmicrostrip and dipole shapes, the antenna resulted in an overall larger bandwidth, low sidelobe level, and higher gain and efficiency. [ABSTRACT FROM AUTHOR]

In this article, a novel low profile wideband high gain stacked microstrip antenna (MSA) array is proposed. This technique of enhancing gain and bandwidth of MSA array is novel and unique and not reported in literature to the best of authors' knowledge. Bandwidth of MSA array is enhanced using reactive impedance surface (RIS) and slotted artificial magnetic conductor (AMC) surfaces while gain of the antenna is improved using four parasitic patches (PPs) placed above the patches of 2×2 MSA array for the first time. Electromagnetic coupling among nearby resonant frequencies of patches of MSA array, RIS, slotted AMC and PPs, provide wide bandwidth. The proposed structure is simple to design and has low profile and smaller dimensions. The antenna provides 12.3 dBi peak gain and 24.6% bandwidth from 5.0-6.4 GHz, which covers 5G, WLAN, and satellite C-band. 1.52 0×1.52 0 × 0.1 0 antenna has Front to back lobe (F/B) ratio >20dB, side lobe level (SLL) <-20 dB and cross-polar level (CPL) <-18 dB. 0 is freespace wavelength at 5.7GHz. The structure offers better radiation parameters, smaller dimensions, and simple design techniques than the reported state of art antennas in the literature. The measured results of prototype fabricated antenna agree with simulated results. The proposed antenna is suitable for transceiver where the two WLAN bands can be used separately for transmission and reception, access point, 5G-V2X and satellite communication. [ABSTRACT FROM AUTHOR]

Background: The presence of peripheral inflammatory cells has been linked to the prognosis of cancer. This study aims to investigate the distinct roles of absolute neutrophil count (ANC) and absolute monocyte count (AMC) in differentiating renal cell carcinoma (RCC) from renal angiomyolipoma (RAML), as well as their prognostic significance in RCC. Methods: We conducted a comprehensive analysis of peripheral immune cell data, clinicopathological data, and tumor characteristics in patients diagnosed with RCC or RAML from January 2015 to December 2021. Receiver operating characteristic (ROC) curves, as well as univariate and multivariate analyses, were employed to assess the diagnostic utility of AMC and ANC in differentiating between RCC and RAML. Kaplan-Meier curve analysis was used to study the survival of RCC patients with different AMC and ANC. The prognostic value of AMC and ANC in RCC was investigated using COX univariate and multivariate analysis. The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were used for bioinformatic correlation analysis. Results: A total of 1120 eligible patients were included in the study. The mean preoperative AMC and ANC in patients with RCC were found to be significantly higher compared to those in patients with RAML (P = 0.001 and P 3.205 *10^9/L was identified to be independently associated with the presence of RCC (HR = 1.618, P = 0.008). High AMC and ANC were significantly associated with reduced OS and PFS (P

The present study addresses advanced monitoring techniques for particles and airborne molecular contaminants (AMCs) in cleanroom environments, which are crucial for ensuring the integrity of semiconductor manufacturing processes. We focus on quantifying particle levels and a representative AMC, hydrogen chloride (HCl), having known detrimental effects on equipment longevity, product yield, and human health. We have developed a compact laser sensor based on open-path cavity ring-down spectroscopy (CRDS) using a 1742 nm near-infrared diode laser source. The sensor enables the high-sensitivity detection of HCl through absorption by the 2-0 vibrational band with an Allan deviation of 0.15 parts per billion (ppb) over 15 min. For quantifying particle number concentrations, we examine various detection methods based on statistical analyses of Mie scattering-induced ring-down time fluctuations. We find that the ring-down distributions’ 3rd and 4th standard moments allow particle detection at densities as low as ~105 m−3 (diameter > 1 μm). These findings provide a basis for the future development of compact cleanroom monitoring instrumentation for wafer-level monitoring for both AMC and particles, including mobile platforms.

The role of MgAl2O4 particles in Al matrix composites has been very crucial. They have evolved from acting as a product at the matrix-reinforcement interface of some ex-situ aluminium matrix composites (AMCs) to a separate reinforcement in the in-situ AMCs. In recent times, they have also been used as a nucleating agent in the form of Al–MgAl2O4 master alloy to propagate the grain refinement process in commercial Al alloys for microstructural changes. In this context, this work reviews the recent developments of MgAl2O4 formation in Al–Mg–Al2O3 and Al–Mg–SiC composites. It summarizes the influence of MgAl2O4 on surface morphology and mechanical characteristics during their formation at the matrix-reinforcement interface. Furthermore, a thorough study on the impact of MgAl2O4 as a reinforcement formed via the in-situ reactive synthesis in AMCs using Al–Mg matrix and different oxide sources namely SiO2, TiO2, and H3BO3 has been carried out. Various results on the grain refinement process obtained using MgAl2O4 as a heterogeneous nucleating agent in Al alloys have been also deliberated in this review.

A wideband, low-profile, dual-polarized antenna using a metasurface (MS) is proposed in this paper. This design consists of a pair of crossed dipoles, an MS, a metal cavity and two baluns. The proposed MS acts as an artificial magnetic conductor (AMC), which is designed for the ±90° reflection-phase bandwidth of 1.4–2.9 GHz. Compared with the 0.25λ0 profile of the traditional crossed dipoles, the profile is reduced to 0.15λ0 by using the in-phase reflection characteristics of the MS, which realizes the utilization of space. The measured results show that the antenna has a 10 dB return loss of 68.2% with isolation of more than 30 dB (1.45–2.95 GHz). The realized gain is 9 dBi with ±1 dBi variation, especially exceeding 10 dBi from 2.1 to 2.8 GHz. [ABSTRACT FROM AUTHOR]

Automated Modulation Classification (AMC) stands as a foundational technique within non-cooperative communication systems, showcasing its intrinsic adaptability to various intricate environments. This study encompasses a dual-phase approach: the initial phase involves the design of eight distinct digital modulation transceivers utilizing LabVIEW NXG, followed by their practical implementation in real-world scenarios through the Universal Software Radio Peripheral (USRP)-X310 a Software Defined Radio (SDR) technology at the microwave frequencies 915 MHz, 2.45 GHz, and 3 GHz carrier frequencies. Subsequently, the second phase entails the retraining of three pre-trained Convolutional Neural Network (CNN) algorithms - MobileNet-V2, ResNet-50, and ResNet-18 - for the purpose of accurately classifying the 16 Ms/sec received modulated signals. The proposed methodology attains impressive accuracy rates of approximately 94.64% for MobileNet-V2, 92.86% for ResNet-50, and 96.43% for ResNet-18, respectively. [ABSTRACT FROM AUTHOR]

Additive manufacturing in construction (AMC) enables new design methods and strategies within the construction industry. In particular, Shotcrete 3D Printing (SC3DP) offers a high degree of design freedom by enabling the deposition of concrete at variable layer orientation based on a wet-mix shotcrete process. However, the mechanical properties and geometry of the printed layers are dependent on the material and process parameters used. In this context, the effects of air and concrete flow rates, path planning parameters, and material parameters have been investigated in previous research. The presented study investigates the influence of the nozzle geometry on the resulting strand properties, e.g. strand geometry, layer bond strength, and compressive strength, to evaluate nozzle diameter and length as control parameters for the SC3DP process. Experimental investigations were performed with fixed nozzle diameters between 10 and 30 mm and nozzle lengths ranging from 100 to 200 mm. The results show a significant influence of the nozzle diameter on the resulting strand geometry as well as the mechanical properties. Finally, concepts for a nozzle with a controllable outlet diameter were developed and evaluated. [ABSTRACT FROM AUTHOR]

In this paper, design and development of a broadband printed dipole antenna is presented. Broadband performance is achieved by compressing the third order mode toward the first resonant mode. For this, the feed gap of the dipole is modified in the form of a symmetrical step in the feed gap. Operating frequency range of this antenna is 2.56 GHz to 7.8 GHz with 10 dB return loss. This dipole antenna is made directional using an Artificial Magnetic Conductor (AMC) as a reflector. This AMC reflector consists of an array of modified EBG cells of Compact Uniplanar Photonic Band Gap (UC-PBG). The UC-PBG Cell is modified by using cross-slot in it to have wide band characteristics compared to original UC-PBG. For performance optimisation of the dipole antenna, the parametric study is carried out in terms of variation in feed gap parameters. Simulated and measured results for dipole and dipole with AMC reflector are presented. [ABSTRACT FROM AUTHOR]

This study documents the industrial conditions that permitted the green-lighting and production of The Walking Dead (2010–2022) on AMC, a network that built its reputation through high-brow series like Mad Men (2007–2015) and Breaking Bad (2008–2013). The findings challenge two major arguments forwarded to make sense of the show's airing: 1) the diagnostic model which suggests that zombies dovetailed into a zeitgeist-coloured paranoia of Others and the aftereffects of a neoliberalised social order and 2) the reputation model, which maintains that the industry track records of the personnel behind projects significantly enhances the chances of receiving a green-light. [ABSTRACT FROM AUTHOR]

In this paper, a novel low profile planar inverted-F antenna (PIFA) with high gain and low specific absorption rate (SAR) using a miniaturized artificial magnetic conductor (AMC) is investigated. The performance of the PIFA antenna is analyzed with AMC to understand the contribution of AMC. The gain enhancement of the PIFA antenna is achieved by applying AMC below the antenna. Furthermore, the placement of AMC also reduces the SAR of the antenna and improves the antenna front-to-back ratio (FBR). The proposed antenna when measured has an impedance bandwidth of 4.8–6.7 GHz (33% with center frequency at 5.75 GHz) which is suitable for Wireless Local Area Network (WLAN), satellite uplink C-band, and sub-6 5G applications with the maximum gain of 7.6 dBi. The performance of the proposed antenna is analyzed by full-wave commercial electromagnetic software and verified by measurements. [ABSTRACT FROM AUTHOR]

This paper introduces a deep learning (DL)-based Automatic Modulation Classification (AMC) model. Our model is considered to be a receiver with a modulation classifier that is capable of differentiating ten modulation techniques. The classifier combines the residual neural network (ResNet) and the long short-term memory network (LSTM). The ResNet boosts the accuracy in deep neural networks, and LSTM improves the classifier’s performance by passing the time-series previous state information to the current state. This paper demonstrates that the proposed model achieves 92% peak recognition accuracy at 18 dB SNR. It is higher than the ResNet by 11.4%, the CNN network by 4.7%, and the CLDNN network by 2%. Moreover, it delivers more than 90% classification accuracy at SNR above 0 dB. Additionally, it improves the classification accuracy at low SNR by achieving 85.5% accuracy at −2 dB SNR. Furthermore, it advances the recognition accuracy of various modulation recognition methods by more than 98% at SNR above 0 dB.

A low-profile broadband $2\times 2$ printed slot array with V-shaped slots by loading broadband artificial magnetic conductor (AMC) is demonstrated. A proposed wideband printed array with tapered V-shaped slots with the feeding of coplanar-waveguide (CPW) is measured in 8.24-11.13 GHz. Also, the proposed wideband planar AMC surface is embedded into the printed array to attain enhanced radiation properties. The printed slot array with the $7\times 7$ AMC surface covers -10 dB measured bandwidth from 4.47 to 13.32 GHz (100%). The design loaded by AMC compared to the design without AMC introduces a reduced size of 109.4%, a bandwidth improvement of 70%, and good impedance matching. Moreover, by adding an AMC surface into the printed array, an enhanced gain of 12.3 dBi with uni-directional radiation patterns is attained. The measured gain over the wide bandwidth shows acceptable stability with an average gain of almost 11 dBi. The proposed AMC unit cell is proposed to resonate at 10.10 GHz with a bandwidth of 7.85-12.24 GHz (43.7%) for X-band applications. In addition, the proposed equivalent transmission line model of the antenna with AMC is presented with acceptable output results. This model forecasts the input impedance of the printed array with AMC at the frequency band of 4.50-13.30 GHz as well.

A $2\times 2$ array of printed antenna loaded by planar Giuseppe Peano artificial magnetic conductor (AMC) is presented for vehicular wireless systems. The four-element of the proposed array by utilizing diverse polarized directions of the printed dipoles with a $5\times 5$ AMC reflector achieves a wideband antenna with enhanced properties. It shows the measured S-parameters of the wide bandwidths from 3.30 to 6.02 GHz with increased stable gains and efficiencies (more than 90%) for all elements. Moreover, the appropriate isolation of greater than 30 dB between the elements is achieved. The proposed design of the printed dipoles includes T-shaped microstrip dipoles and a feedline system as a T-shape to broaden the bandwidth in 4.7-6.02 GHz ( $\text{S}_{11}\le $ -10 dB). By utilizing the $3\times 3$ Giuseppe Peano AMC reflector into the one element of the printed dipole, enhanced radiation efficiency and −10 dB measured bandwidth from 3.26 to 6.02 GHz (60%) is achieved for vehicular wireless systems. The proposed design with AMC with respect to the antenna without AMC indicates a reduced size of 70%, increased gain up to 8.4 dBi, and uni-directional radiation patterns. The new AMC unit cell is configured by the Giuseppe Peano design to resonate at 5.36 GHz in 4.27-6.34 GHz (39%). Finally, the suggested equivalent transmission line model of the $2\times 2$ array with AMC surface is introduced with a suitable agreement between the results of reflection coefficients.

Automatic modulation classification (AMC) has recently acquired a lot of interest in the optical wireless communication (OWC) community. The OWC channel has variable characteristics. Hence, there is a need for an adaptive modulation scheme to cope with the varying channel characteristics. Adaptive modulation requires the implementation of AMC at the receiver side. Instead of using complex classification with deep learning (DL) techniques, a simple proposed scheme for AMC is introduced in this paper. This scheme is based on chaotic Baker map (CBM), wavelet image fusion, and autocorrelation estimation. It depends on constellation diagrams for eight modulation formats, including (2/4/8/16 PSK), and (8/16/32/64 QAM). First, the constellation diagrams are acquired and scrambled through the CBM, and they are merged using the wavelet image fusion and stored as reference templates in the system database. After that, the classification of each modulation format depends on estimated correlation scores and a thresholding strategy similar to the strategy adopted in cancellable biometric systems that depend on encrypted templates. Simulation results prove good classification for all studied modulation formats. [ABSTRACT FROM AUTHOR]

A gain enhanced dual-band filtenna operating at frequency bands of 3.5 and 5.3 GHz for 5G sub-6 GHz applications is presented in this article. A dual-band antenna is integrated with a filter to improve selectivity. The antenna uses printed monopoles as the radiating element, and the filtering response is achieved using a modified feedline. The designed filtenna is 50 × 38 × 1.63 mm3 in size with a maximum gain of 2.5 dBi. The novel filtenna design is equipped with an artificial magnetic conductor (AMC) for the first time to enhance the performance. A unit cell for the AMC is designed that offers zero phase shift in the desired frequencies. A four by four AMC array is designed using this unit cell, which is used as a reflective surface to improve the radiation characteristics of the filtenna. The gain of the filtenna is improved three times up to 7.5 dBi in both bands. The proposed design's overall planar dimensions are 80 × 80 mm2. Using AMC, the gain has improved with a very minute or no change in the other characteristics. The measured results are congruent with the simulated ones, illustrating that the filtenna has good impedance matching and excellent gain in both bands. [ABSTRACT FROM AUTHOR]

Particle-reinforced aluminium matrix composites (AMC) with a high-volume fraction of ceramic reinforcement (>30 vol.%) combine high specific strength and stiffness with good wear resistance and thermal stability, resulting in their increasing popularity in high-load applications, such as brake discs and bearings. It is hence assumed that AMC will accumulate as scrap in the near future. Appropriate recycling strategies must therefore be developed to maintain AMC's inherent properties. Melt-metallurgical recycling routes bear the danger of dissolving the ceramic reinforcement in the liquid metallic matrix and contaminating primary melts or forming intermetallic phases in secondary melts. Here, a solid-state AMC recycling route with crushing and sintering is investigated, wherein all steps are carried out below the solidification temperature of the aluminium matrix. A sintered primary AMC is mechanically converted into a particulate/powdery secondary raw AMC in coarse, medium, and milled quality (i.e., with d ≈ 7–12 mm, d ≈ 3–7 mm, and d < 300 µm) and subsequently resistance heating sintered to a secondary AMC under a variation of the sintering pressure. The two AMC generations are analysed and discussed regarding their microstructure and mechanical properties. Since the secondary AMC show reduced the mechanical strength, the fracture surfaces are analysed, revealing iron contaminations from the mechanical processing. [ABSTRACT FROM AUTHOR]

For the future application of wireless power transfer on the human body, a wearable directional button antenna, composed of 2 × 3 artificial magnetic conductor (AMC) cells, is proposed, where the kinetic energy antenna is put on the elbow, which then charges the receiving communication antenna on the upper arm. The radiator of the button antenna is a monopole antenna, which is top-loaded by two cylindrical substrates with different radii to achieve a low profile, and it is fed by the microstrip line made by textiles, including 100% cotton substrate and conductive textile. The AMC cells are put close to the feeding microstrip line in order to realize directional radiation to the other side. Meanwhile, a real human arm model of a Chinese women is built to accurately analyze the corresponding wave propagations. Consequently, two identical antenna prototypes are fabricated, and the corresponding measurements are implemented, where an on-arm approximate measurement method for the radiation pattern is proposed. The measurements agree well with the simulations. Additionally, the influence of the communication antenna on the kinetic energy antenna and the interactions between the antenna and the arm are analyzed. Finally, the transmission efficiency and the SAR values are investigated. [ABSTRACT FROM AUTHOR]

A 5G wireless system requests a high-performance compact antenna device. This research work aims to report the characterization and verification of the artificial magnetic conductor (AMC) metamaterial for a high-gain planar antenna. The configuration is formed by a double-side structure on an intrinsic dielectric slab. The 2-D periodic pattern as an impedance surface is mounted on the top surface, whereas at the bottom surface the ground plane with an inductive narrow aperture source is embedded. The characteristic of the resonant transmission is illustrated based on the electromagnetic virtual object of the AMC resonant structure to reveal the unique property of a magnetic material response. The characteristics of the AMC metamaterial and the planar antenna synthesis are investigated and verified by experiment using a low-cost FR4 dielectric material. The directional antenna gain is obviously enhanced by guiding a primary field radiation. The loss effect in a dielectric slab is essentially studied having an influence on antenna radiation. The verification shows a peak of the antenna gain around 9.7 dB at broadside which is improved by 6.2 dB in comparison with the primary aperture antenna without the AMC structure. The thin antenna profile of /37.5 is achieved at 10GHz for 5Gevolution. The emission property in an AMCstructure herein contributes to the development of a lowprofile and high-gain planar antenna for a compact wireless component. [ABSTRACT FROM AUTHOR]

Solid state sintering of cast aluminum powders by resistance heating sintering (RHS), also known as spark plasma sintering or field-assisted sintering technique, creates a very fine microstructure in the bulk material. This leads to high performance material properties with an improved strength and ductility compared to conventional production routes of the same alloys. In this study, the mechanical behavior of an RHS-sintered age-hardenable A357 (AlSi7Mg0.6) cast alloy and a SiCp/A357 aluminum matrix composite (AMC) was investigated. Aiming for high strength and good wear behavior in tribological applications, the AMC was reinforced with a high particle content (35 vol.%) of a coarse particle fraction (d50 = 21 µm). Afterwards, separated and combined effects of particle reinforcement and heat treatment were studied under compressive load both at room temperature and at 350 °C. At room temperature compression, the strengthening effect of precipitation hardening was about twice as high as that for the particle reinforcement, despite the high particle content. At elevated temperatures, the compressive deformation behavior was characterized by simultaneously occurring temperature-activated recovery, recrystallisation and precipitation processes. The occurrence and interaction of these processes was significantly affected by the initial material condition. Moreover, a rearrangement of the SiC reinforcement particles was detected after hot deformation. This rearrangement lead to a homogenized dispersion of the reinforcement phase without considerable particle fragmentation, which offers the potential for secondary thermo-mechanical processing of highly reinforced AMCs.

This study focuses on the production of stir-squeeze cast hybrid composites made of aluminium with reinforcements. Base metal AA6105 is combined with SiC/TiC. TiC is changed from 3 to 9 wt% while SiC is kept constant (3wt%).Nine specimens are created using the deviation of the stir casting parameters of Stirrer speed (SP) 350-550rpm, Stir-time (TI) 15-25 min, and Reinforcement (RE) 3-19 w.t% in accordance with L9 Taguchi's design. By applying pressure of 60 MPa during squeeze casting, reinforced composites are created. Both stir casting and squeeze cast specimens are examined for their mechanical characteristics, such as tensile strength (TS) and hardness (BHN). Based on elongation, tension, and strain, TS was assessed for both processes. The outcomes showed that SQC sample L6 obtained the maximum TS of 303.19 MPa while STC specimen only managed to reach 269.88 MPa. The STC method produced a hardness value of roughly 83.56 Hv, whereas the greatest hardness value of 94.73 Hv was obtained with SQC sample L9 (SP-550 rpm, TI-25 min & RE-6%).

This paper introduces a deep learning (DL)-based Automatic Modulation Classification (AMC) model. Our model is considered to be a receiver with a modulation classifier that is capable of differentiating ten modulation techniques. The classifier combines the residual neural network (ResNet) and the long short-term memory network (LSTM). The ResNet boosts the accuracy in deep neural networks, and LSTM improves the classifier's performance by passing the time-series previous state information to the current state. This paper demonstrates that the proposed model achieves 92% peak recognition accuracy at 18 dB SNR. It is higher than the ResNet by 11.4%, the CNN network by 4.7%, and the CLDNN network by 2%. Moreover, it delivers more than 90% classification accuracy at SNR above 0 dB. Additionally, it improves the classification accuracy at low SNR by achieving 85.5% accuracy at −2 dB SNR. Furthermore, it advances the recognition accuracy of various modulation recognition methods by more than 98% at SNR above 0 dB. [ABSTRACT FROM AUTHOR]

As a result of resource constraints in each generation of wireless systems, new technologies should be used in order to obtain maximum system efficiency. The combination of Adaptive Modulation and Coding (AMC) with Generalized Frequency Division Multiplexing (GFDM) is a promising technique which efficiently optimizes the data rate, increases the capacity and reduces Bit Error Rate (BER) of the systems, which are primary goals of each generation of wireless networks. In paper, we primarily analyze multicarrier GFDM performance based on adaptive modulation using a discrete rate, then examine a variable power transmission scheme and finally find the form of rate and power which maximizes the spectral efficiency. The results show that significant improvement in terms of spectral efficiency and BER can be achieved demonstrating the superiority of the proposed AMC scheme in comparison with nonadaptive transmission schemes. Therefore, the presented system can be used in next generation cellular networks with higher capacity. [ABSTRACT FROM AUTHOR]

This article presents a low-profile and flexible dualband AMC Antenna operating at 2.45/ 5.8 GHz for wireless local area network (WLAN) on-body antenna applications using textile materials. A dual-band artificial magnetic conductor (AMC) structure with a dual hexagonal shape was used to reduce back radiation, therefore specific absorption rate (SAR), and improve the antenna performance parameters. To study the antenna/body interaction, a suitable comprehension and detailed studies of the wave propagation in the vicinity of the human arm in different meteorological conditions were carried out to demonstrate the effects of the skin condition on the antenna performance parameters. The simulation and measurement results indicate that electromagnetic communication on wet skin is viable. Acceptable SAR values were obtained, revealing that the body is well immune from the antenna electromagnetic radiation in functional wearable conditions. The proposed wearable AMC antenna provided engaging simulation and measurement results. It satisfies users' comfort and safety properties, making it a good candidate for WLAN/WBAN applications.

A flexible wearable antenna with wideband characteristics and having a conical radiation pattern which is suitable for ON body application is presented. To realize a compact antenna size, characteristic modal (CM) analysis is performed initially, and the ground plane of the antenna is utilized to generate one of the resonant modes. The quasi-current loop in the feed layer patch is used to generate another resonant mode. Combination of these two modes has resulted in the wideband performance of the antenna from 4.72 to 6.08 GHz. A planar wideband artificial magnetic conductor (AMC) is used beneath the antenna. This AMC surface compensates the undesired coupling taking place due to the ground radiator thereby reducing the specific absorption rate (SAR) to 76.4% and enhancing the gain of the antenna. The performance of the antenna in terms of return loss, gain, efficiency, SAR and bending sensitivity is studied.

Efficient utilisation of adaptive modulation and coding ensures the quality transmission of information bits through the significant reduction in bit error rate (BER). Channel prediction using parametric estimation is not efficient for massive machine-type communication (mMTC) devices under the 5G New Radio (NR). In this paper, we have proposed a channel prediction scheme based on a deep learning (DL) algorithm possessed by parametric analysis. In deep learning, the pipeline methodology is used along with the image processing technique to predict the channel condition for optimal selection of the adaptive modulation and coding (AMC) profile. The deep learning-based pipelining approach utilises image restoration (IR) and image super-resolution (SR). The super-resolution method is used to de-noise the low-pixel 2-D image that is obtained from the parametric value of the beacon to predict the channel condition. The estimation results are compared with the conventional minimum mean square error (MMSE) and an approximation to the linear MMSE (ALMMSE) method, which is obtained through channel state information (CSI). The comparison results show that the parametric-enabled deep learning approach is superior, especially in poorer channel conditions. The performance of BER through parametric estimation along with the DL approach is ~66% more efficient as compared to the conventional MMSE method for BPSK mapping.

The aluminum-based composites (AMCs) are known for a variety of functions like building, aerospace, automotive, marine, and aeronautical applications. In this research, Al-4032 alloy-based 6% SiC (by weight) composite has been fabricated using stir casting and the effects of prominent machining parameters on energy consumption and surface finish have been examined using carbide inserts in turning. Microstructures of as-cast specimens has been analyzed using the optical microscope, scanning electron microscopy, and energy-dispersive spectroscopy. The CNC turning has been performed at varying machining parameters like cutting speed, feed rate, and depth of cut, following an RSM-based design matrix. The desirability function approach has been employed to obtain the best combination of parameters for achieving the desired objectives. The experimental outcome demonstrates that the machined composite is considerably influenced by built-up edge (BUE) formation and interfacial bonding of particles. The result establishes that the inclusion of SiC in the Al-4032 matrix demonstrates improved mechanical properties and superior machined surface with the optimized turning operation. [ABSTRACT FROM AUTHOR]

All textile integrated dual-band monopole antenna with an artificial magnetic conductor (AMC) is proposed. The proposed design operates at 2.4 and 5.8 GHz for wearable medical applications to monitor the heartbeat. A flexible and low-profile E- shaped CPW dual-band textile antenna is integrated with a 4 × 4 dual-band textile AMC reflector to enhance the gain and specific absorption rate (SAR). The SAR is reduced by nearly 95% at both 1 and 10 g. The design was measured on the body with a 2 mm separation. The simulated and measured results appear in high agreement in the case of with and without AMC array integration. The measurement was performed in the indoor environment and in an anechoic chamber to validate the design based on reflection coefficient and radiation pattern measurements. [ABSTRACT FROM AUTHOR]