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Abstract This article presents a compact, wide-angle, polarization-insensitive metamaterial harvester that can efficiently harvest electromagnetic (EM) energy in the S, C, X, and Ku bands. The harvester's unit cell consists of a split ring resonator, two strip lines, and two split strip lines, giving it a total size of (10 × 10) mm2. Each split gap is filled with a 50 Ω resistive load. The input impedance of the harvester is precisely designed to match that of free space, allowing for efficient absorption of EM power and appropriate redirection towards the resistive loads. The harvester's performance is also evaluated for various polarization and incident angles, considering the Transverse Electric and Transverse Magnetic modes. The simulation results reveal that the proposed harvester exhibits a notably greater conversion efficiency of around > 95%. The simulation outcomes were carefully validated through experimental tests conducted in an anechoic chamber using a 3 × 3 cell array of the proposed design. This ensured the accuracy and reliability of the results. The strong correlation between the experimental data and the full-wave simulations strongly supports the effectiveness of the proposed harvester. Therefore, the demonstrated efficiency and compact size make it a perfect fit for energy harvesting systems in wireless sensor networks.

This research paper demonstrates a metamaterial (MTM) based sensing technique to detect various blood samples by analyzing their dielectric properties. The performance of this MTM-based sensor is evaluated with the help of mimicked human blood samples that closely resemble the dielectric properties of actual human blood samples. Moreover, the ISM band frequency of 2.4 GHz is chosen as one of the reference resonance frequencies due to its various industrial and medical applications. The resonating patch is developed on the FR-4 substrate with a dimension of 10 × 20 mm2 that provides sharp reference resonances of 2.4 and 4.72 GHz for the spectra of the transmission coefficient with a good quality factor (Q-factor). The MTM sensor can detect the mimicked blood samples with a maximum frequency deviation of up to 650 MHz at 2.4 GHz and up to 850 MHz at 4.72 GHz, with maximum sensitivity of 0.917 and 0.707, respectively. The measured results using the prototype of the sensor support the simulation result with good agreement, indicating high sensing capability. Due to its high sensitivity, figure of merit (FoM), and frequency shifting with dielectric property changes in blood samples, the developed MTM-based sensor can be implemented effectively for quick sensing of infected blood samples and biomedical applications.

Abstract Breeding programs require exhaustive phenotyping of germplasms, which is time-demanding and expensive. Genomic prediction helps breeders harness the diversity of any collection to bypass phenotyping. Here, we examined the genomic prediction’s potential for seed yield and nine agronomic traits using 26,171 single nucleotide polymorphism (SNP) markers in a set of 337 flax (Linum usitatissimum L.) germplasm, phenotyped in five environments. We evaluated 14 prediction models and several factors affecting predictive ability based on cross-validation schemes. Models yielded significant variation among predictive ability values across traits for the whole marker set. The ridge regression (RR) model covering additive gene action yielded better predictive ability for most of the traits, whereas it was higher for low heritable traits by models capturing epistatic gene action. Marker subsets based on linkage disequilibrium decay distance gave significantly higher predictive abilities to the whole marker set, but for randomly selected markers, it reached a plateau above 3000 markers. Markers having significant association with traits improved predictive abilities compared to the whole marker set when marker selection was made on the whole population instead of the training set indicating a clear overfitting. The correction for population structure did not increase predictive abilities compared to the whole collection. However, stratified sampling by picking representative genotypes from each cluster improved predictive abilities. The indirect predictive ability for a trait was proportionate to its correlation with other traits. These results will help breeders to select the best models, optimum marker set, and suitable genotype set to perform an indirect selection for quantitative traits in this diverse flax germplasm collection.

The neuron is sometimes referred to as the “head” or “central” cell of the nervous system since it has the ability to communicate with other neurons or cells via electrical impulses. The hardware realization and simulation of these neurons are critical in neuromorphic engineering. In this paper, we made a device that generates 4 different spiking patterns of the nervous system as a Spike Generator (SG) using a hybrid approximation of the target model called the Piece-Wised Power-2 Based Izhikevich Model (PWP2BIM). This proposed model works in a low-cost state to achieve a correct digital implementation of the Izhikevich model, one of the main neuron models (i.e. decreasing hardware resources and enhancing speed and accuracy). The proposed model successfully reproduces the behavioral traits of the initial neuron model. To verify the results of the mathematical simulation, the proposed model was synthesized and implemented on the Zynq XC7Z010 (3CLG400) reconfigurable board (FPGA). The findings of hardware synthesis and applications of the suggested paradigm demonstrate that certain biological behaviors may be duplicated more effectively and at a significantly lower cost. The suggested model’s frequency can be increased using this technique (implemented on the Zynq board) at least by 3.6 times compared to the original model, and power consumption can be decreased by 28%. High-frequency design of neuronal models with low-cost attributes is required for application-based types of equipment in case of high-speed operations of these components. Thus, using our approach, the desired goals of application-based features are to be fulfilled. In addition, because the suggested model uses fewer hardware resources than the original model, it is feasible to construct a significantly higher number of neurons (approximately 5 times) on a single Zynq board.

This research provides a detailed explanation of the design, simulation, and experimental of quad-square metamaterial-based negative-index unit cells for S-band applications. The Computer Simulation Technology 2022 licensee version was utilized to design and obtain numerical results for the unit cell. The proposed unit cell for the metamaterial has dimensions of 5 × 5 × 1.57 mm3. The substrate chosen was FR-4, resulting in a substantial effective medium ratio value of 19.07. A series of systematic parametric studies were conducted to optimize the quad square metamaterial structure. Key parameters, such as substrate types, unit cell arrays, thicknesses of substrate, and split gaps, were varied to determine their impact on the structure. The validated equivalent circuit result was compared to the simulated results, showing a significant agreement. The demonstrated correlation between simulation and experimental data highlights the dependability of the proposed quad-square metamaterial, positioning it as a viable option for a range of electromagnetic applications, such as communication systems, sensors, and imaging devices.

This paper introduces a metamaterial energy harvester that is compact, highly efficient, and capable of operating at wide angles. The proposed design has an outer ring resonator housing inverted T-shaped resonators, and it can operate at two distinct frequencies, 3.2 GHz and 5.4 GHz. The structure's impedance is carefully designed to align with that of free space, ensuring efficient capture of incident electromagnetic power with minimal reflection. This enables the resistor load to receive power in the most efficient manner. Based on the simulation findings, the proposed harvester exhibits a notably higher conversion efficiency of around 97 %. To ensure the accuracy and reliability of the simulation outcomes, we fabricated a 3x3 cell array of the proposed design and conducted experimental tests within an anechoic chamber. The simulation and experimental results exhibit a strong correlation. Existing metamaterial-based energy harvesting designs frequently confront size, absorption band, and polarization sensitivity limitations. Our compact design is distinguished by its ability to accomplish near-unity absorption and greater power conversion efficiencies at the desired frequency bands. This makes it an ideal option for energy harvesting systems for wireless sensor networks prioritizing efficiency and size.

In this paper, a novel metamaterial sensor with excellent sensitivity and quality factor for microwave sensing applications is presented. The designed metamaterial sensor is assembled on a 1.575 mm thickness of low-cost dielectric substrate material (Rogers RT5880), and the copper is used as a resonator. Computer Simulation Technology version 2019 (CST-2019) software is employed to design and analyze the proposed metamaterial sensor. In addition, the Advanced Design System version 2016 (ADS 2016) software is used to validate the CST simulated model. Subsequently, the simulated results were validated using laboratory measurements. The optimized cell is small; its dimension is 10 × 10 mm2, and the obtained resonances are 3.85 and 6.85 GHz with notches of −26.29 and −40.03 dB, respectively. The textile material is detected by the resonance frequency change, and this frequency is dependent on the material’s permittivity values. To test the developed sensor’s sensing capabilities, three types of textiles—wool, fleece, and denim—are used. The effective medium ratio, sensitivity, and Q-factor of the structure are evaluated, and the obtained values are 8.96, 14.57%, and 345, respectively. The sensor for detecting textile materials works in the S and C bands. The resonances are shifted 530 MHz between the air and wool, 420 MHz between the air and fleece, and 640 MHz between the air and denim. The simulated outcomes and laboratory results almost matched. The projected sensor can be employed in the apparel sector to identify textile materials because it is small, inexpensive, has a high quality factor, and has high sensitivity.

This article presents a novel real-time meta-material (MM) sensor based on a non-invasive method that operates in microwave frequency ranges at 8.524 GHz to measure blood glucose levels with quality factor 184 is designed and fabricated. A cross enclosed between two square shapes produces a strong interaction between glucose samples and electromagnetic waves. In this study, 5 were tested noninvasively using the proposed glucose resonant sensor with a range of glucose-level changes from 50 to 130 mg/dL. For this range of glucose-level changes, the frequency detection resolution is 5.06 MHz/(mg/dL), respectively. Despite simulations, fabrication procedures (F.P.) have been carried out for more precise result verification. For the purpose of qualitative analysis, the proposed MM sensor is considered a viable candidate for determining glucose levels.

State-of-the art research on conventional microwave substrates reveals limitations of restricted flexibility, poor adaptability to irregular surfaces, and reduced effectiveness in complex sensing environments, leading to the development of a flexible microwave substrate using Co–Ca ferrite for feasible applications in detecting industrial chemicals. In this paper, CoxCa (0.90-x) Ni0.10Fe2O4 (x = 0.25, 0.50, and 0.75) based flexible substrate is developed through the sol-gel method, and a rectangular enclosed cross-dumbbells (RECD) metamaterial structure is designed for industrial chemical contamination sensing. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) are used to morphological analysis of the nanoparticles of the substrate. XRD patterns shows the presence of crystalline phases, which facilitate the determination of strain within these materials. FESEM images demonstrate a structural composition characterized by nanosized grains and capillary-nanopores, where these nanosized grains are found uniformly distributed across the film's surface and results structural homogeneity. The synthesized nanoparticles are employed as a solid substrate utilizing PVA (polyvinyl alcohol) to ensure a uniform structure. The dielectric constant of the developed substrate is measured using the DAK 3.5 dielectric measurement kit, and it shows dielectric permittivity values ranging from 1.77 to 3.32 with loss tangents ranging from 0.031170 to 0.1929 for x = 25 % to x = 75 %. Metamaterial characteristics of the fabricated RECD structure on Co–Ca ferrite is analysed and μ-negative characteristics is achieved from 4.7 GHz to 6 GHz. Additionally, the reflection coefficient of the RECD metamaterial is also investigated for different bending condition up to an angle of 30ο. The simulated and measured S21 results strongly match each other. The sensing performance is evaluated for three concentrations of methanol and ethanol, demonstrating excellent contamination sensing capabilities with sequential frequency shifting. This study undoubtedly revealed that Co–Ca ferrite-based flexible metamaterial have great potential for high performance industrial chemical contamination sensing applications.

This paper provides a metamaterial for microwave absorbers relying on asymmetric square split rings with a partial E shape in the centre-based resonator. The wideband frequency range shows its sensing capabilities in identifying various oil samples. The optimized MTM unit cell has electrical dimensions of 0.122λο × 0.122λο, where is λο the predicted wavelength at 3.64 GHz resonance frequency, for a total size of 10 × 10 mm2. The FR-4 dielectric substrate, 1.6 mm in thickness, produces the unit cell. The MTM has a maximum absorption peak of 91.46 % at 3.64 GHz, 99.72 % at 5.99 GHz, 96.89 % at 7.47 GHz, and 98.45 % at 10.01 GHz. This MMA has four absorption peaks, making it suitable for use in the triple band (S, C, and X). The centre split gaps and partial E shapes increase unit cell absorption, and the defective CSRR back layer structure improves the transmission coefficient. High absorption is influenced by the central split gaps and an appropriate electric field and magnetic field optimized in the centre ring when the structure is in an Orthogonal orientation. The research used a frequency domain solver operating between 2 and 12 GHz. The scattering characteristics (coefficient of transmission) of the relevant unit cell's equivalent circuit were confirmed using ADS software and the CST result. At frequencies between 3 and 5 GHz, the proposed asymmetric unit cell functions as a double negative (DNG) metamaterial absorber due to its negative permeability and permittivity. Since oil samples have different dielectric constants, the resonance frequency and Q factor are likewise different. Here, we receive a spectrum of frequencies that can be adjusted for use in sensing. The data showed that the suggested sensor is sensitive enough to pick up a variety of oils. The proposed sensor is useful for various applications, from liquid detection to microfluidic sensing and beyond, due to its cheap cost, high sensitivity, high-quality factor, and high electromagnetic radiation (EMR).

Abstract Metamaterials have gained much attention due to their exciting characteristics and potential uses in constructing valuable technologies. This paper presents a double negative square resonator shape metamaterial sensor to detect the material and its thickness. An innovative double-negative metamaterial sensor for microwave sensing applications is described in this paper. It has a highly sensitive Q-factor and has good absorption characteristics approximately equal to one. For the metamaterial sensor, the recommended measurement is 20 by 20 mm. Computer simulation technology (C.S.T.) microwave studios are used to design the metamaterial structure and figure out its reflection coefficient. Various parametric analyses have been performed to optimize the design and size of the structure. The experimental and theoretical results are shown for a metamaterial sensor that is attached to five different materials such as, Polyimide, Rogers RO3010, Rogers RO4350, Rogers RT5880, and FR-4. A sensor’s performance is evaluated using three different thicknesses of FR-4. There is a remarkable similarity between the measured and simulated outcomes. The sensitivity values for 2.88 GHz and 3.5 GHz are 0.66% and 0.19%, respectively, the absorption values for both frequencies are 99.9% and 98.9%, respectively, and the q-factor values are 1413.29 and 1140.16, respectively. In addition, the figure of merit (FOM) is analyzed, and its value is 934.18. Furthermore, the proposed structure has been tested against absorption sensor applications for the purpose of verifying the sensor's performance. With a high sense of sensitivity, absorption, and Q-factor, the recommended sensor can distinguish between thicknesses and materials in various applications.

This study introduces a Metamaterial 'M.M.' sensor designed and evaluated to detect pure and adulterated fuels and oils. The reflection coefficient was measured using advanced design systems and computer simulations, followed by computational and experimental analyses of the performance evolution of the proposed sensor. The proposed sensor was evaluated using samples of varying compositions of Coconut Oil 'C.O.', petrol and kerosene. The results demonstrated a noticeable change in the Resonance Frequency 'R.F.' of the samples upon modification of their concentration. The reflection coefficient values for petrol and a 20 % combination of kerosene were determined to be −44.81 dB at a frequency of 10.29 GHz and −41.07 dB at a frequency of 10.15 GHz. Similarly, for coconut oil and refined coconut oil, the reflection coefficient values were found to be −47.34 dB at a frequency of 11.239 GHz and −41.981 dB at a frequency of 11.15 GHz. The sensor exhibits a high-quality factor of 451.58, a good sensitivity value of 5.65 and a figure of merit of 2551.427, indicating its excellent performance and efficiency. The results demonstrate the versatility of the proposed sensor, making it suitable for a range of applications such as microfluidics and industrial settings.

A unique shaped metamaterial sensor is proposed for detecting a wide range of pure and adulterated fuels and oils. The functionality of the designed structure has been examined both theoretically and practically ways, and the results show that it performs incredibly well. A new sample holder is built for more convenient functioning, and it is attached directly behind the constructed structure. In the field of research on liquids sensing, the purpose of this work was to present an alternative methodology. The CST microwave studio software is used to test a variety of different designs to determine which ones would result in the resonator having the best possible dimensions. The resonance frequency shifted 270, 410, and 180 MHz; between pure petrol and a mixture of 20 % kerosene and 80 % petrol, 100 % diesel and a mixture of 20 % ethanol and 80 % diesel, and clean olive oil and a mixture of 20 % corn oil and 80 % olive oil, respectively. The sensor has a quality factor of 430, high sensitivity of 1.99, and a figure of merit of 855.70, which indicates that it performs well and efficiently. In addition, the sensor that has been presented can accurately differentiate between various liquids by making use of the frequency shifting feature. The findings obtained demonstrate that this concept is readily applicable for a wide variety of electrochemical sensing applications even if the permittivity of the sample is altered; this is indicated by the findings. Because the sensor that is recommended possesses high sensitivity, a high-quality factor, and outstanding performance, it is suitable for use in the fuel industry, oil industry, and microfluidics industry.

The paper presents the preparation and measurement of six-layered human head phantoms for the sensor-based microwave brain imaging system (SMBIS) for the diagnosis of tumors in the head. The head phantom has been constructed based upon three-dimensional arrangements filled-up with numerous biochemical combinations that imitate the six brain tissues: DURA, CSF, White Matter, Gray Matter, Fat, and Skin regarding permittivity within the wideband frequency band (1 GHz to 4 GHz). For imaging purposes, the malignant and benign tumor(s) are also fabricated and placed in different locations in the 3D skull model to validate the performance of the phantom. After being formulated, the dielectric properties are measured by utilizing a dielectric kit linked with a vector network analyzer. The measured dielectric properties are compared to real human head tissue’s dielectric properties. After that, the human phantom model, including tumors, is validated using a SMBIS. The investigational dielectric characteristics of the brain tissues showed good agreement with the dielectric properties of the real brain tissues of the head. The experimental imaging outcomes demonstrated the legitimacy of the proposed six-layered tissue mimicking phantoms that can be used as an alternate to the actual human brain tissue for the diagnosis of brain tumors in SMBIS.

A novel Compact Complementary Split Ring Resonator (CSRR) metamaterial unit cell with perfect absorption, beneficial for ambient power harvesting, is proposed to operate in the S- and C-band. The size of the structure is 15 × 15 × 1.575 mm3 with dimensions of 0.18λ0 × 0.18λ0 × 0.019λ0 at the lowest absorption frequency. The proposed compact-sized CSRR structure exhibits notable characteristics such as high absorption coefficients and polarization-insensitive behaviours across a wide range of angles. The results demonstrate a notably high absorption efficiency of 97%, 99%, and 98% at 3.7275 GHz, 4.7075 GHz, and 5.9325 GHz. A 3 × 3 array is designed and verified by experimental results. The proposed design exhibits superior performance compared to previously published designs, which suffer from significant limitations such as a large metamaterial structure, reduced absorption frequency bands, and a lower fraction of absorption bands. The proposed design exhibits potential for utilization in developing wireless sensor network applications that require compact and highly efficient harvesting systems.

Abstract Broadband absorbers are required for solar energy harvesting because they efficiently absorb the incident photon in the wide-ranging solar spectrum. To ensure high absorption of photons, metamaterial absorbers (MMAs) have been a growing area of interest in recent years. In this article, an MMA is proposed using a metal–insulator–metal (MIM) structure (Ni–SiO2–Ni) that shows a near-unity broadband absorption of wavelengths from 300 to 1600 nm, with a 95.77% average absorption and a peak absorption of 99.999% at 772.82 nm. The MMA is polarization insensitive as well as wide incident angle stable. Analysis of the effects of mechanical bending on the absorption of the proposed structure shows that absorption holds satisfactory values at different degrees of mechanical loading. The suggested MMA unit cell structure was computationally simulated using the Finite Integration Technique (FIT) and verified using the Finite Element Method (FEM). To analyze the feasibility of the proposed MMA as a solar cell, it is investigated with the universal AM 1.5 solar spectrum characteristics. Besides solar energy harvesting, the proposed MMA unit cell may be employed in a variety of diverse optical applications, including sensors, detectors, and imaging.

In this article, a meander line with parasitic resonator based on ENG metamaterial is introduced, with nonlinear regression of sensitivity for sensing applications. The unit cell is manufactured on a dielectric substrate of FR-4 with a thickness of 1.5 mm. The electrical dimension of the optimized cell is 0.098λ×0.094λ, where λ is the calculated wavelength at 7.2 GHz resonance frequency. A sensor has been designed by the unit cell to measure the thickness of the polypropylene. The offered metamaterial architecture exhibits resonance frequency 7.2 GHz at C-band with the amplitude of −21.72 dB. The NRW approach based MATLAB software shows properties with an ENG behavior and permeability close to zero. For the analysis procedure, a frequency domain solver with the frequency range of 2–12 GHz was used. ADS software verified the scattering parameters (coefficient of transmission) of the equivalent circuit for the corresponding unit cell with the CST result. The result indicates that this design has SNG features at C-band. The EMR (effective medium ratio) of this suggested unit cell is 10.60 at 7.2 GHz resonance frequency. The bandwidth of the optimized cell is 6.75–7.36 GHz, and the negative permittivity region is 7.2–7.8 GHz 1 × 2, 2 × 2, 4 × 4, and 16 × 16 array of unit cell results have been examined. All the array results show the same with the unit cell. Substrate material has also been changed to see the effect of resonance frequency in the parametric study. Finally, the proposed meander line structure performance was further simulated numerically and experimentally investigated for sandwich combination thickness sensing. It shows a narrow bandwidth sensing range between 6.25 and 6.47 GHz with significant sensitivity (S) and accuracy. The design complies with superior effective medium parameters and affords miniaturization factor for the size. Due to its low profile and high EMR, the planned ENG metamaterial can be a suitable C-band aspirant for sensing applications.

A non-invasive, low-powered, and portable electromagnetic (EM) head imaging system is presented using metamaterial (MTM) loaded compact directional 3D antenna. The antenna consists of two slotted dipole elements with $2\times 3$ and $3\times 3$ finite MTM array elements in top and ground, respectively, and folded parasitic elements that operate within the frequency range of 1.12 GHz to 2.5 GHz. The MTM array elements are optimized to enhance the overall performance regarding antenna bandwidth, realized gain, efficiency, and directionality in both free space and proximity to the head model. The mathematical modelling is also analyzed to justify the integration of MTM unit cells to the top and ground side of the antenna. The impact of MTM on SAR analysis is also performed. A tissue-mimicking 3D head phantom is fabricated and measured to validate the antenna performance. A nine-antenna portable setup is used with the fabricated phantom to measure and collect the scattering parameters that are later analyzed to detect and reconstruct the haemorrhage images by applying the updated IC-CF-DMAS algorithm. The overall performance demonstrates the feasibility of the proposed system as a portable platform to successfully detect, locate and monitor the haemorrhages inside the head in EM imaging system.

In this paper, the triple reflection band split O circled T (SOCT) shape metamaterial resonator is presented based on the transmission line principle. This paper aims to develop a miniature metamaterial resonator that can simultaneously perform as a reflector and a sensing element in the microwave range. Compare to symmetric and asymmetric structures; the reflection feature is mostly available in a typical resonating structure. The primary motivation beyond the presented work is to achieve high reflection with triple resonance points at 5.8 GHz, 6.37 GHz and 6.57 GHz. The proposed structure achieved Double Negative (DNG) features on this particular resonance with a relative permittivity value ranges −2.17 to −6.62 and relative permeability of −0.73 to −4.15. The scattering parameter performance was verified through simulation and measurement for unit cell and $5\times 8$ array structure. An analytical sensing ability for liquid salinity was performed for potential microwave application, which indicates a potential outcome of the proposed structure in microwave sensing applications.

In this research paper, the sensing capabilities of a tri circle split ring resonator shaped metamaterial is shown within the X-band frequency range for detection of various oil samples both theoretically and experimentally. Mathematical modelling was used to analyze the sensor efficiency for the various oil samples. A new sample holder has been made for the proposed sensor structure, and it showed significant performance. The simulated and measured transmission coefficient has been revealed in this study and monitoring the shift of resonance frequency and sensitivity of the metamaterial sensor for different oil samples. Since the dielectric constants of the oil samples differ, hence the resonance frequency is shifted. The obtained result revealed that the proposed sensor can detect a wide range of liquids, including (i) coconut and extra virgin coconut oils, (ii) olive and extra virgin olive oils, (iii) clean and waste engine oils, (iv) sunflower and canola oils. The resonance frequency has shifted to about 210, 230, 170, and 200 MHz for the above-mentioned oil samples, respectively. The sensitivity of the proposed MTM sensor is −83 dB (mg/L) which is a new analysis and quite significant as a potential sensor structure. Surface current and electric field distributions were used to deduce the sensing process. Since the recommended sensor is cheap and highly sensitive; so, it can be used in a variety of fields, such as detection of various liquids, microfluidic sensing, and industrial applications.

This paper reports a central spiral split-rectangular-shaped metamaterial absorber surrounded by a polarization-insensitive ring resonator for s-band applications. The rated absorption is 99.9% at 3.1 GHz when using a three-layer structure where the top and ground are made of copper and the center dielectric material is a commonly used FR-4 substrate. The central split gaps have an impact on the unit cell by increasing high absorption, and an adequate electric field is apparent in the outer split ring gap. At 3.1 GHz, the permittivity and permeability are negative and positive, respectively, so the proposed unit cell acts as an epsilon negative (ENG) metamaterial absorber. In a further analysis, Roger4450B was used as a substrate and obtained excellent absorption rates of 99.382%, 99.383%, 99.91%, and 95.17% at 1.44, 3.96, 4.205, and 5.025 GHz, respectively, in the S- and C-band regions. This unit cell acts as a single negative metamaterial (SNG) absorber at all resonance frequencies. The S11 and S21 parameters for FR-4 and Rogers4450B were simulated while keeping the polarization angle (θ and φ) at 15, 30, 45, 60, 75, and 90 degrees to measure, permittivity, permeability, reflective index, absorption, and reflection. The values of the reflective index are near zero. Near-zero reflective indexes (NZRI) are widely used in antenna gain propagation. The unit cell fabricated for the FR-4 substrate attained 99.9% absorption. S-band values in the range of (2–4) GHz can be applied for low-frequency radar detection.

Estimation of genetic diversity in rapeseed is important for sustainable breeding program to provide an option for the development of new breeding lines. The objective of this study was to elucidate the patterns of genetic diversity within and among different structural groups, and measure the extent of linkage disequilibrium (LD) of 383 globally distributed rapeseed germplasm using 8,502 single nucleotide polymorphism (SNP) markers. We divided the germplasm collection into five subpopulations (P1 to P5) according to geographic and growth habit-related patterns. All subpopulations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise Fst comparison revealed a great degree of divergence (Fst > 0.24) between most of the combinations. The rutabaga type showed highest divergence with spring and winter types. Higher divergence was also found between winter and spring types. Admixture model based structure analysis, principal component and neighbor-joining tree analysis placed all subpopulations into three distinct clusters. Admixed genotype constituted 29.24% of total genotypes, while remaining 70.76% belongs to identified clusters. Overall, mean linkage disequilibrium was 0.03 and it decayed to its half maximum within < 45 kb distance for whole genome. The LD decay was slower in C genome (< 93 kb); relative to the A genome (< 21 kb) which was confirmed by availability of larger haplotype blocks in C genome than A genome. The findings regarding LD pattern and population structure will help to utilize the collection as an important resource for association mapping efforts to identify genes useful in crop improvement as well as for selection of parents for hybrid breeding.

Abstract This paper reports on a tunable transmission frequency characteristics-based metamaterial absorber of an X band sensing application with a fractional bandwidth. Tunable resonator metamaterial absorbers fabricated with dielectric surface have been the subject of growing attention of late. Absorbers possess electromagnetic properties and range modification capacity, and they have yet to be studied in detail. The proposed microstructure resonator inspired absorber with triple fractional band absorption consists of two balanced symmetrical vertical patches at the outer periphery and a tiny drop hole at two edges. Experimental verification depicted two absorption bands with single negative (SNG) characteristics for two resonances, but double negative (DNG) for single resonance frequency. The mechanism of sensing and absorption was analyzed using the transmission line principle with useful parameter analysis. Cotton, a hygroscopic fiber with moisture content, was chosen to characterize the proposed absorber for the X band application. The electrical properties of the cotton changed depending on the moisture absorption level. The simulation and the measured absorption approximately justified the result; the simulated absorption was above 90% (at 10.62, 11.64, and 12.8 GHz), although the steady level was 80%. The moisture content of the cotton (at different levels from 0 to 32.13%) was simulated, and the transmission resonance frequency changed its point in two significant ranges. However, comparing the two adopted measurement method and algorithm applied to the S parameter showed a closer variation between the two resonances (11.64 and 12.8 GHz) which signified that a much more accurate measurement of the cotton dielectric constant was possible up to a moisture content of 16.1%. However, certain unwanted changes were noted at 8.4–8.9 GHz and 10.6–12.4 GHz. The proposed triple-band absorber has potential applications in the X band sensing of moisture in capsules or tablet bottles.

Abstract Background A sustainable breeding program requires a minimum level of germplasm diversity to provide varied options for the selection of new breeding lines. To maximize genetic gain of the North Dakota State University (NDSU) flax breeding program, we aimed to increase the genetic diversity of its parental stocks by incorporating diverse genotypes. For this purpose, we analyzed the genetic diversity, linkage disequilibrium, and population sub-structure of 350 globally-distributed flax genotypes with 6200 SNP markers. Results All the genotypes tested clustered into seven sub-populations (P1 to P7) based on the admixture model and the output of neighbor-joining (NJ) tree analysis and principal coordinate analysis were in line with that of structure analysis. The largest sub-population separation arose from a cluster of NDSU/American genotypes with Turkish and Asian genotypes. All sub-populations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise F st comparison revealed a great degree of divergence (F st > 0.25) between most of the combinations. A whole collection mantel test showed significant positive correlation (r = 0.30 and p 0.50). In contrast, low genetic differentiation between P5 and P2 may enhance the accumulation of favorable alleles for oil and fiber upon crossing to develop dual purpose varieties. As each sub-population consists of many genotypes, a Neighbor-Joining tree and kinship matrix assist to identify distantly related genotypes. These results also inform genotyping decisions for future association mapping studies to ensure the identification of a sufficient number of molecular markers to tag all linkage blocks.

Abstract Solar energy is one of the ambient sources where energy can be scavenged easily without pollution. Intent scavenging by the solar cell to recollect energy requires a state-of-the-art technique to expedite energy absorption to electron flow for producing more electricity. Structures of the solar cell have been researched to improve absorption efficiency, though most of them can only efficiently absorb with narrow-angle tolerance and polarization sensitivity. So, there is a strong demand for broadband absorption with minimal polarization sensitivity absorber, which is required for effective solar energy harvesting. In this paper, we proposed a new Split Hexagonal Patch Array (SHPA) shape metamaterial absorber with Double-negative (DNG) characteristics, which will provide a wide absorption band with low polarization sensitivity for solar spectrum energy harvesting. The proposed new SHPA shape consists of six nano-arms with a single vertical split which with arrowhead symmetry. This arm will steer electromagnetic (EM) resonance to acquire absolute negative permittivity and permeability, ensuring DNG property. This DNG metamaterial features analyzed based on the photoconversion quantum method for maximum photon absorption. The symmetric characteristics of the proposed structure enable the absorber to show polarization insensitivity and wide incident angle absorption capabilities. Simulated SHPA shows a visible and ultraviolet (UV) spectrum electromagnetic wave absorption capacity of more than 95%. The quantum method gives an advantage in the conversion efficiency of the absorber, and the numerical analysis of the proposed SHPA structure provides absorbance quality for THz regime energy harvesting through solar cell or photonic application.

Researchers are trying to work out how to make a broadband response metamaterial absorber (MMA). Electromagnetic (EM) waves that can pass through the atmosphere and reach the ground are most commonly used in the visible frequency range. In addition, they are used to detect faults, inspect tapped live-powered components, electrical failures, and thermal leaking hot spots. This research provides a numerical analysis of a compact split ring resonator (SRR) and circular ring resonator (CRR) based metamaterial absorber (MMA) using a three-layer substrate material configuration for wideband visible optical wavelength applications. The proposed metamaterial absorber has an overall unit cell size of 800 nm × 800 nm × 175 nm in both TE and TM mode simulations and it achieved above 80% absorbance in the visible spectrums from 450 nm to 650 nm wavelength. The proposed MA performed a maximum absorptivity of 99.99% at 557 nm. In addition, the steady absorption property has a broad range of oblique incidence angle stability. The polarization conversion ratio (PCR) is evaluated to ensure that the MMA is perfect. Both TM and TE modes can observe polarization insensitivity and wide-angle incidence angle stability with 18° bending effects. Moreover, a structural study using electric and magnetic fields was carried out to better understand the MMA’s absorption properties. The observable novelty of the proposed metamaterial is compact in size compared with reference paper, and it achieves an average absorbance of 91.82% for visible optical wavelength. The proposed MMA also has bendable properties. The proposed MMA validation has been done by two numerical simulation software. The MMA has diverse applications, such as color image, wide-angle stability, substantial absorption, absolute invisible layers, thermal imaging, and magnetic resonance imaging (MRI) applications.

In this paper, we present a computational analysis method for the study of silicon dioxide (SiO2) graphene-based and amorphous silicon (a-Si)-graphene based nano meta-atoms in the terahertz (THz) regime. The proposed meta-atoms were modeled using a SiO2 substrate, optimized using a-Si substrate, and “sandwiched” between graphene layers. The octagonal-shaped torus was geometrically designed as a 3D structure to achieve optimal electromagnetic wave absorption from separate atoms. The upper and lower tori had identical diagonal arms to capture the maximum number of photons with minimal absorption losses. Graphene was chosen as the upper and ground layer material to optimize the electrical and optical properties of our proposed nano metamaterial. Finally, the following four fractional bandwidths with absorption percentages were optimized from the simulation: 4 bands (225.7–254.74 THz, 99.8%; 356.64–401.1 THz, 97.28%; 525.4 THz, 99.19%; 656.34 THz, 94.94%). The multi-band fractional absorption characteristic in the THz regime highlighted our proposed nano meta-atom as a potential candidate for absorption in the infrared and visible spectrum.

This paper reports, a metasurface absorber which is U-joint loaded Double Split O shaped with a square split patch at the center and Double Negative (DNG) property. The proposed absorber shows significant absorption for potential applications like radar signal absorption and satellite communication, remote sensing, RF shielding. The vertical U joint and split O mutually creates substantial resonance and expedite by the center square patch, to cover two consecutive X and Ku band absorption peaks at 11.56 GHz with 82.31%, 12.27 GHz with 98.91% and 14.19 GHz with 97.79%. Besides, balanced geometrical shape with insensitivity polarization for TE and TM mode wave propagation enhances the robustness and tunability of the structure. The absorption mechanism analyzed and discussed with the Finite Integration Technique (FIT). Characterization of S-parameter executed with an established method for dielectric property extraction and finally compared the proposed absorber with existing literature. Keywords: Metamaterial, Absorber, DNG, Wideband, Ku band

Objective: The study was conducted to estimate the proportionate prevalence of dog bite in cattle, goats and dog at selected veterinary hospitals in Bangladesh and India, and to assess the farmers' knowledge level about dog bite and rabies in general. Materials and methods: A 4-month prospective study was conducted to evaluate the prevalence of dog bite in different species at selected veterinary hospitals in Bangladesh and India during January to July 2015. A total of 119 dog bite cases were identified by anamnesis, manifesting signs and clinical and physical examinations. Information about site of bite, duration, bite management, vaccination history, rabid dog, breed, age, sex and knowledge about rabies were composed by extensive cross-questioning to the farmers using pre-structured questionnaire. Results: The proportionate prevalence was found higher in goats (25.7%) irrespective of study placements. Hind leg (28-50%) and hind quarter (13-34%) of all species were found as the most vulnerable body part for dog bite. Younger (8-26%) and female (6-36%) animals were more prone to attack by dog. About 65% farmers had preliminary knowledge about rabies and they were aware about high fatality rate of this disease. Most of the respondents (about 45%) said that they did not know about how many days required to occur rabies after the animal being bitten by a rabid dog. Around 70% people had knowledge about source of rabies vaccine, and 74% people thought that the Government Veterinary Hospital was the main source of post exposure rabies vaccine. After dog biting, out of 119, 106 victims were recovered as a result of proper washing and dressing of biting site, and administration of post exposure rabies vaccine. Conclusion: Dog bite was higher in younger and female animals as compared to males and adult animals with an exception in case of dog. [J Adv Vet Anim Res 2016; 3(3.000): 252-258]

A low-profile high-directivity, and double-negative (DNG) metamaterial-loaded antenna with a slotted patch is proposed for the 5G application. The radiated slotted arm as a V shape has been extended to provide a low-profile feature with a two-isometric view square patch structure, which accelerates the electromagnetic (EM) resonance. Besides, the tapered patch with two vertically split parabolic horns and the unit cell metamaterial expedite achieve more directive radiation. Two adjacent splits with meta units enhance the surface current to modify the actual electric current, which is induced by a substrate-isolated EM field. As a result, the slotted antenna shows a 7.14 dBi realized gain with 80% radiation efficiency, which is quite significant. The operation bandwidth is 4.27–4.40 GHz, and characteristic impedance approximately remains the same (50 Ω) to give a VSWR (voltage Standing wave ratio) of less than 2, which is ideal for the expected application field. The overall size of the antenna is 60 × 40 × 1.52 mm. Hence, it has potential for future 5G applications, like Internet of Things (IoT), healthcare systems, smart homes, etc.

This paper presents an oval-shaped sensor design for the measurement of glucose concentration in aqueous solution. This unit cell sensing device is inspired by metamaterial properties and is analytically described for better parametric study. The mechanism of the sensor is a sensing layer with varying permittivity placed between two nozzle-shaped microstrip lines. Glucose aqueous solutions were characterized considering the water dielectric constant, from 55 to 87, and were identified with a transmission coefficient at 3.914 GHz optimal frequency with double negative (DNG) metamaterial properties. Consequently, the sensitivity of the sensor was estimated at 0.037 GHz/(30 mg/dL) glucose solution. The design and analysis of this sensor was performed using the finite integration technique (FIT)-based Computer Simulation Technology (CST) microwave studio simulation software. Additionally, parametric analysis of the sensing characteristics was conducted using experimental verification for the justification. The performance of the proposed sensor demonstrates the potential application scope for glucose level identification in aqueous solutions regarding qualitative analysis.

In this paper, a dual-band metamaterial absorber (MMA) ring with a mirror reflexed C-shape is introduced for X and Ku band sensing applications. The proposed metamaterial consists of two square ring resonators and a mirror reflexed C-shape, which reveals two distinctive absorption bands in the electromagnetic wave spectrum. The mechanism of the two-band absorber particularly demonstrates two resonance frequencies and absorption was analyzed using a quasi-TEM field distribution. The absorption can be tunable by changing the size of the metallic ring in the frequency spectrum. Design and analysis of the proposed meta-absorber was performed using the finite-integration technique (FIT)-based CST microwave studio simulation software. Two specific absorption peaks value of 99.6% and 99.14% are achieved at 13.78 GHz and 15.3 GHz, respectively. The absorption results have been measured and compared with computational results. The proposed dual-band absorber has potential applications in sensing techniques for satellite communication and radar systems.

Antimicrobial resistance has emerged as a significant health problem worldwide, including in Bangladesh, where chickens are an important protein source for human nutrition. One of the factors accelerating the development of antimicrobial resistance is the inappropriate use of antimicrobials on commercial chicken farms. A cross-sectional study was conducted in 2019 on 140 commercial chicken farms in the Chattogram district of Bangladesh to investigate the association between antimicrobial use and resistance in Escherichia coli and Salmonella spp. cultured from cloacal swabs of chickens and from the poultry shed environment. All E. coli and Salmonella spp. isolates were resistant to multiple antimicrobial classes, including those categorized as “Highest Priority Critically Important Antimicrobials” for human medicine. Notably, resistance was observed in E. coli isolates from farms that did not use these antimicrobial classes in the current production cycle. For example, although quinolones were not used on 43.9% of E. coli positive farms, 95.7% of these farms had quinolone-resistant E. coli isolates. The results of the path analysis revealed that there was a “direct effect” of the frequency of antimicrobial usage on “high” resistance, with resistance increasing when antimicrobials were administered more frequently (β  =  0.28, p  =  0.002). There was a “direct effect” of the purpose of antimicrobial use on “low” resistance, with resistance marginally decreasing when antimicrobials were administered solely for therapeutic use (β  = −0.17, p  =  0.062), but increasing when they were used prophylactically. Overall, the study results could be used to educate farmers on better practices for antimicrobial administration, and to guide government agencies to update policies on antimicrobial use and resistance surveillance in the poultry sector of Bangladesh. [ABSTRACT FROM AUTHOR]