Showing papers in "Progress in Electromagnetics Research M in 2017"
TL;DR: Propagation parameters, such as distance between transmitting and receiving antennas, transmitting power and terrain elevation, were used as inputs to Artificial Neural Network for the development of an ANN based path loss model, which performed better than basic empirical path loss models considered.
Abstract: Propagation path loss models are useful for the prediction of received signal strength at a given distance from the transmitter; estimation of radio coverage areas of Base Transceiver Stations (BTS); frequency assignments; interference analysis; handover optimisation; and power level adjustments. Due to the differences in: environmental structures; local terrain profiles; and weather conditions, path loss prediction model for a given environment using any of the existing basic empirical models such as the Okumura-Hata’s model has been shown to differ from the optimal empirical model appropriate for such an environment. In this paper, propagation parameters, such as distance between transmitting and receiving antennas, transmitting power and terrain elevation, using sea level as reference point, were used as inputs to Artificial Neural Network (ANN) for the development of an ANN based path loss model. Data were acquired in a drive test through selected rural and suburban routes in Minna and environs as dataset required for training ANN model. Multilayer perceptron (MLP) network parameters were varied during the performance evaluation process, and the weight and bias values of the best performed MLP network were extracted for the development of the ANN based path loss models for two different routes, namely rural and suburban routes. The performance of the developed ANN based path loss model was compared with some of the existing techniques and modified techniques. Using Root Mean Square Error (RMSE) obtained between the measured and the model outputs as a measure of performance, the newly developed ANN based path loss model performed better than the basic empirical path loss models considered such as: Hata; Egli; COST-231; Ericsson models and modified path loss approach.
27 citations
TL;DR: In this paper, a compact size, dual-band antenna is proposed for WLAN/WiMAX/LTE 2500/DMB applications, which consists of radiating strips with half hexagonal and vertical rectangular shapes and square-shaped ground plane.
Abstract: In the present work, a compact size, dual-band antenna is proposed for WLAN/WiMAX/LTE 2500/DMB applications. The designed antenna is fed by a 50 Ω coplanar line. The radiating component of the composed antenna consists of radiating strips with half hexagonal and vertical rectangular shapes and square-shaped ground plane which are printed on the same layer. The overall size of the antenna substrate is only 10× 24× 1.6 mm3. The simulated and measured results of the proposed antenna show that it operates in the frequency range from 2.5 GHz to 2.75 GHz and 5.0 GHz to 6.7 GHz, respectively.
25 citations
TL;DR: An octagonal shape monopole antenna with dual band-notched features used for ultra wide band applications is presented in this paper, which has good impedance matching from 3.4 GHz to 12 GHz.
Abstract: An octagonal shape monopole antenna with dual band-notched features used for ultra-wide band applications is presented. The monopole antenna has good impedance matching from 3.4 GHz to 12 GHz. The dual notched bands are achieved by using a U-shaped parasitic strip and meandered slot etched in the radiating patch. The first band notched is achieved using meandered slot to reduce the interference with WIMAX from 3.3 to 3.9 GHz. The second band notched is achieved using a U-shaped parasitic strip placed above the ground plane to eliminate the interference with WLAN from 5.2 GHz to 5.9 GHz. The proposed antenna is designed, simulated and measured. The measured result shows that the antenna structure achieves (VSWR < 2) from 3.2 to 10.8 GHz. Also, the simulated radiation pattern and current distribution at different frequencies are presented. The measured and simulated results confirm that the proposed antenna is suitable for UWB applications.
24 citations
19 citations
TL;DR: In this article, the effect of percentage loading of nanosize carbon black (CB) on DC conductivity, dielectric and microwave absorption properties and electromagnetic Shielding Effectiveness (SE) of silicone rubber composites is studied.
Abstract: In this paper, studies on broadband microwave absorption and electromagnetic shielding effectiveness are reported in flexible rubber composites with low filler content of nanosize conducting carbon over 8–18 GHz frequency range of electromagnetic spectrum. Rubber based composites are prepared by loading of 1–15 wt% nanosize conducting Carbon Black (CB) in silicone rubber matrix. Effect of percentage loading of nanosize CB on DC conductivity, dielectric & microwave absorption properties and electromagnetic Shielding Effectiveness (SE) of silicone rubber composites is studied. The percolation threshold is achieved at low concentration (3 wt%) of CB in composites. The observed complex permittivity values revealed that composites with concentration of 5wt% CB can provide more than 90% microwave absorption (Reflection Loss > −10 dB) over 8–18 GHz at composite thickness of 1.9–2.7 mm. Further, composites with concentration of 15 wt% of CB shows −40 dB SE over the broad frequency range 8–18 GHz at thickness 2.8 mm. The effect of composite thickness on microwave absorption properties and shielding effectiveness is also analyzed. Thus, the prepared rubber composites with suitable concentration of nanosize CB as filler may be used as microwave absorber in stealth applications as well as for EMI shielding of electronic equipments in various civilian and military areas.
19 citations
TL;DR: In this paper, a symmetrically structured meander line antenna placed around a T-shaped junction with truncated ground planes is proposed for wearable applications, which has a percentage bandwidth of 69.04% covering the GSM 1800 band industrial scientific and medical (ISM) 2.4-2.5 GHz band.
Abstract: In this paper, a symmetrically structured meander line antenna placed around a T-shaped junction with truncated ground planes is proposed for wearable applications. The designed antenna has a percentage bandwidth of 69.04% covering the GSM 1800 band industrial scientific and medical (ISM) 2.4–2.5 GHz band, 4G LTE band 7 (2.5–2.69 GHz). The antenna is compact in nature with a size of 30×40×1.6 mm3. SAR reduction is achieved without the attachment of any additional unit. It is found that the application of designed truncated ground planes around positions of high electric field (E-field) region is an effective solution for reduction of Specific Absorption Rate (SAR) significantly through field cancellation technique. Maximum temperature elevation due to electromagnetic wave absorption has also been computed. The antenna is simulated over a homogenous human dry skin model as well as over a head model. The proposed design is fabricated and measured, and it is found to be compatible for real world applications while considering its miniaturization, radiation patterns and SAR limitations.
19 citations
TL;DR: In this article, a Quad Rectangular Shaped Microstrip Antenna (QRSMA) is proposed for multiband operation with a single microstrip line feed, which can be applied to L (1-2 GHz), S (2-4 GHz) and C (4-8 GHz) bands.
Abstract: This paper presents a Quad-Rectangular Shaped Microstrip Antenna (QRSMA) fed by a single microstrip line feed. QRSMA having different frequency bands is designed to be applied to L (1–2 GHz), S (2–4 GHz) and C (4–8 GHz) bands applications. QRSMA is loaded with a single square patch and 4 rectangular patches. The patches are loaded using a flame retardant substrate (Fr-4). The patches are connected with 1 mm width of copper (Cu) strip-line. Thus the proposed design of patches and width is responsible for desired multiband operations. The antenna resonates at frequencies f1 = 1.074, f2 = 3.119, f3 = 4.089, f4 = 5.683 and f5 = 6.514 GHz. Thus, the antenna is useful in the L, S and C band applications. Compared to other antenna designs, the proposed antenna exhibits multiband performance, size reduction and is economical. It also realizes tunability of frequencies having stable radiation pattern with compact electrical size. The paper analyses the simulated and experimental results. Various cases of QRSMA performances are also compared in this paper.
18 citations
TL;DR: In this article, an equivalent expression for the quantum radar cross section expression, including the alternate form written in terms of Fourier transforms, can be derived using quantum scattering theory applied to non-relativistic, massive particles.
Abstract: The quantum radar cross section (QRCS) is a concept that gives information on the amount of returns (or scattered energy towards the detector) one can expect from a particular target when being illuminated with a small number of photons. This cross section is highly dependent on the target’s geometry, as well as the illumination angle and the scattering angle from the target. The expression for the quantum radar cross section equation has been derived in the context of photon scattering. In this paper, it will be shown that an equivalent cross section expression, including the alternate form written in terms of Fourier transforms, can be derived using quantum scattering theory applied to non-relativistic, massive particles. Both single particle and multiple particle illumination are considered. Although this approach is formulated based upon massive, non-relativistic particle scattering, its equivalence to the expression based upon photon scattering provide many valuable insights of representing and interpreting these equations in the context of quantum radar. This includes an improved algorithm to simulate the QRCS response of an object illuminated with any number of photons desired.
17 citations
TL;DR: In this paper, the force calculation in a radial passive magnetic bearing using Monte Carlo technique with general division approach (s-MC) with MATLAB programming has been presented and the expression of magnetic force is obtained using magnetic surface charge density method which incurs a multidimensional integration with complicated integrand.
Abstract: This paper represents the force calculation in a radial passive magnetic bearing using Monte Carlo technique with general division approach (s-MC). The expression of magnetic force is obtained using magnetic surface charge density method which incurs a multidimensional integration with complicated integrand. This integration is solved using Monte Carlo technique with 1-division (1-MC) and 2-division (2-MC) approaches with a MATLAB programming. Analysis using established methods such as finite element method (FEM), semi-analytical method, and adaptive Monte Carlo (AMC) method has been carried out to support the proposed technique. Laboratory experiment has been conducted to validate the proposed method. 2-MC gives better result than 1-MC. The computation time of the proposed method is compared with the quadrature method, FEM and AMC. It is observed that the proposed method invites less computational burden than those methods as the algorithm adaptively traverses the domain for promising parts of the domain only, and all the elementary regions are not considered with equal importance.
15 citations
TL;DR: In this paper, a quad band-notched compact ultra-wideband (UWB) patch antenna is presented to operate on the industry, scientific, and medical (ISM) bands.
Abstract: A quad band-notched compact ultra-wideband (UWB) patch antenna to operate on the industry, scientific, and medical (ISM) bands are presented in this study. A modified hexagonal patch vertex-fed with a coplanar waveguide (CPW) is fabricated on an FR-4 substrate with size of 43× 28× 1.6 mm3 and fractional bandwidth of 133%. The compact antenna operates at a frequency of 2.45 GHz, which is often required for the efficient performance of ISM utilisation. The existing bands share the same bandwidth as that of UWB systems. Therefore, a notched band at 3GHz for worldwide interoperability for microwave access (WiMAX), and a further resonance band at 2.45 GHz for ISM are generated by implementing a meander-line strip on the antenna. Furthermore, the design demonstrates a couple of F-shaped slots and an inverted diamond-shaped slot on the patch. Moreover, a pair of Jshaped slots is loaded on the ground plane. The downlink C-band, wireless local area network (WLAN), and downlink X-band are rejected by the proposed slots, respectively. The current distribution, gain, radiation efficiency, and quad notched parameters of the proposed antenna are studied by using CST software. The demonstrated prototype covers an ISM band at (2.2 GHz–2.6 GHz) with a return loss of −23.45 dB and omnidirectional radiation patterns. A good agreement is observed between measured and the simulated results. This paper has presented a solution for both interference and miniaturised issues.
15 citations
TL;DR: In this article, the general principles of design and development of microwave absorbing materials are discussed and analyzed in respect to the 26-37 GHz frequency range (Ka-band), and composites based on carbon nanotubes in epoxy resin matrix are produced, and their electromagnetic responses are investigated in Ka-band.
Abstract: The general principles of design and development of microwave absorbing materials are discussed and analysed in respect to 26–37 GHz frequency range (Ka-band). Dispersive composite materials based on carbon nanotubes in epoxy resin matrix are produced, and their electromagnetic responses are investigated in Ka-band. Both theoretical and experimental results demonstrate that presented composites may be used as compact effective absorbers in 26–37 GHz range.
TL;DR: It is observed that the U-shaped microstrip patch antenna with meandered slots shows good performance with sufficient bandwidth, low losses and is capable of use in biomedical applications.
Abstract: In this paper, a U-shaped microstrip patch antenna with meandered slots is presented. It is designed for biomedical applications to operate at 2.45 GHz. Based on the simulation experience, two designs of the patch are introduced with and without use of meandered slots. The comparative study between these two is also demonstrated. It is observed that the antenna with meandered slots shows good performance with sufficient bandwidth, low losses and is capable of use in biomedical applications. Furthermore, the proposed antenna has small size of 35∗29∗1.6 mm3, and the size of the ground is only 14% of the overall antenna size. The measured and simulated results show good agreement with each other. The antenna is fabricated on an FR4 substrate, and simulation is carried out on FDTD based Empire XCcel simulator.
TL;DR: In this paper, a hybrid-polarity architecture consisting of transmitting circular polarisation and receiving two orthogonal linear polarisation was used to calculate four Stokes parameters, viz. plant height, plant age and plant biomass of cotton crops grown under two different environments, i.e., rainfed and irrigated in Guajrat, India were studied with respect to derived polarimetric parameters.
Abstract: A hybrid-polarity architecture, consisting of transmitting circular polarisation and receiving two orthogonal linear polarisation and also their relative phase, was used to calculate four Stokes parameters. Different parameters like Degree of Polarisation, Alpha angle, Entropy, Anisotropy, Radar vegetation Index and decompositions like Raney decomposition (m-δ), Freeman-2 and 3 component decompositions were derived from these hybrid data. Crop biophysical parameters viz. plant height, plant age and plant biomass of cotton crops grown under two different environments, i.e., rainfed and irrigated in Guajrat, India were studied with respect to derived polarimetric parameters. Right circular transmitted and horizontally (RH) and vertically (RV ) received backscatter values show good relation with the plant height, age and biomass. RH backscatter −13 dB to −7 dB and RV backscatter from −13 to −10 dB were observed for crop biophysical parameters. Volume component of all decomposition showed strong response to the increase in height, age and biomass of the plant. Radar Vegetation index (RVI) values have also shown significant increase from 0.6 to 0.7 with increasing age of the crop. The rate of growth was slow in the initial phase, but fast post mid-July for both early and late sown cases. The polarimetric parameters were found significantly correlated to the above plant biophysical parameters.
TL;DR: In this article, a derivative method based on surface magnetic flux density on circle results in peak at conductor's location, which is recognized by the absence of peak at corresponding conductor's position.
Abstract: Grounding grid is responsible for driving lightning and short circuit currents into ground. Faults in substation grounding grid can lead to significant rise in surface potential and ultimately loss to power system and operators. This paper proposes a novel technique based on derivative method to diagnose breakpoints in grounding grid. Derivative of surface magnetic flux density on circle results in peak at conductor’s location. Once a conductor is broken the flow of current and surface magnetic field ceases, which is recognized by the absence of peak at corresponding conductor’s location. The use of circle even enables this method for diagnosing diagonal branch. Furthermore, the method is analyzed for soil of different resistivities and monolayer and multilayer soils. Simulation results show that the proposed method is feasible for breakpoint diagnosis of grounding grid without excavation.
TL;DR: In this article, a combination of the two-ray path loss model and knife-edge diffraction was used to predict path loss for near-ground and short-range communication applications.
Abstract: In this paper, radio wave propagation over irregular terrain is investigated in 200–600MHz (VHF/UHF band). Measured results are compared with different path loss models such as Fresnel knife edge diffraction and uniform theory of diffraction (UTD). It is shown that, for low antenna heights, using a combination of the two-ray path loss model and knife-edge diffraction, great improvement in path loss prediction accuracy is achieved. The derived model is aimed to effectively predict path loss for near-ground and short-range communication applications.
TL;DR: The proposed robust CCAA beamformer enhances the output power 28.9 dB, 9.34 dB and 1.63 dB at 1◦ disparity angle in comparison to the CCAA standard capon beamformer, robust SCB and existing novel loading technique.
Abstract: The performance of a Concentric Circular Antenna Array (CCAA) is presented in this paper with variable loading technique. A CCAA geometry is chosen because of its symmetrical configuration which enables the phased array antenna to scan azimuthally with minimal changes in its beam width and side-lobe levels. The performance of CCAA system is degraded, if any disparity occurs between the original signal direction and the steering direction of the beamformer. This performance degradation problem due to look direction disparity can be improved by using robust techniques. This paper proposes a technique, named variable diagonal loading (VDL) technique for CCAA system and compares the performance of the proposed robust CCAA processor with existing CCAA processors. The proposed robust CCAA beamformer enhances the output power 28.9 dB, 9.34 dB and 1.63 dB at 1◦ disparity angle in comparison to the CCAA standard capon beamformer (SCB), robust SCB and existing novel loading technique. Numerical examples are presented to analyze the performance of the proposed robust beamformer in different scenarios.
TL;DR: In this paper, the authors analyzed rectangular and circular patch antennas fabricated from meshed conductors and backed with solid ground planes and found that the reduction of certain mesh lines increases the optical transparency with minimal hindrance to the antenna's efficiency.
Abstract: This paper analyzes rectangular and circular patch antennas fabricated from meshed conductors and backed with solid ground planes. Because of the meshing, the antennas are rendered optically transparent, where the transparency is determined by the mesh geometry. It is found that although there is a compromise between the antenna’s efficiency and the optical transparency of the meshed patch, it is possible to optimize the antenna by refining mesh lines to certain extent. The limiting factors for refining mesh lines include material handling and fabrication process as well as the increased line impedance when being refined, which accordingly causes loss in antenna’s efficiency. A refined mesh with thin linewidth increases both antenna performance and transparency. Additionally, it is found that the reduction of certain mesh lines increases the optical transparency with minimal hindrance to the antenna’s efficiency, leading to further enhancement to the see-through percentage. Although it is possible to refine mesh lines to improve the antenna’s efficiency or gain, it is seen that there is a limit for such an optimization method. This limit is closer to the efficiency of a solid patch for a lower transparency, whereas it is lower for increased transparency. Cross polarization level was also examined, and there was no significant effect on such a parameter due to meshing.
TL;DR: In this article, an improved principal component selection rule is proposed for selecting the main components of target signal, and the proposed method can effectively remove the clutter signals and reserve more target information.
Abstract: Principal component analysis is usually used for clutter suppression of ground penetrating radar, but its performance is influenced by the selection of main components of target signal. In the paper, an improved principal component selection rule is proposed for selecting the main components of target signal. In the method, firstly difference spectrum of singular value is used to extract direct wave and strong target signal, and then, Fuzzy-C means clustering algorithm is used to determine the weights of principal component of weak target signal. Finally, the principal components of strong target signal and weak target signal are reconstructed to obtain target signal. Experimental results show that the proposed method can effectively remove the clutter signals and reserve more target information.
TL;DR: In this paper, a novel kind of ideal independent radiation field named the orthogonal radiation field (ORF) is constructed for microwave staring correlated imaging (MSCI), which achieves high resolution imaging results by employing the temporal-spatial-independent radiation field.
Abstract: Microwave staring correlated imaging (MSCI) achieves high resolution imaging results by employing the temporal-spatial independent radiation field. In MSCI, the imaging performance is determined by the independent degree of the radiation field. In this paper, a novel kind of ideal independent radiation field named the orthogonal radiation field (ORF) is constructed for MSCI. Firstly, a group of two-dimensional (2-D) orthogonal basis functions are used to construct the ideal ORF samples. Then a method is proposed to construct the ORF samples by designing the transmitting signals. The numerical simulations validate the feasibility of this method. Finally, when the ORF is applied in MSCI, the numerical simulations achieve high resolution imaging results and demonstrate good imaging performance that is robust to noise.
TL;DR: In this paper, a new design of an oblique incidence and polarization insensitive metamaterial absorber with multiband absorption is presented, which comprises concentric continuous rings of different radii and widths placed in four different quadrants with identical pair of rings placed diagonally opposite with each ring responsible for high absorption.
Abstract: Simulation and experimental measurement of a new design of an oblique incidence and polarization insensitive metamaterial absorber with multiband absorption is presented in this paper. The unit cell of the proposed metamaterial absorber comprises concentric continuous rings of different radii and widths placed in four different quadrants with identical pair of rings placed diagonally opposite, with each ring responsible for high absorption. The calculated dispersion behavior of MM absorber in terms of effective permittivity (εeff ), effective permeability (μeff ), and refractive index (ηeff ) shows the metamaterial characteristics. The surface current and field distributions in MM absorber are simulated to understand the occurrence of absorption bands. The measured results show the absorption peaks of 99.5%, 99.8%, 99.5% and 99.9% at 7.20 GHz, 9.3 GHz, 12.61 GHz, and 13.07 GHz, respectively. The simulated results are well supported by the experimentally measured performance of the fabricated metamaterial absorber. It offers multiband absorption with bands lying in C-band, X-band and Kuband for mobile communication, satellite communication and radar applications. With merged third and fourth absorption peaks, the proposed metamaterial absorber structure exhibits a broadband absorption.
TL;DR: In this article, a multiband wearable fractal antenna suitable for GPS, WiMax and WiFi (Bluetooth) applications is presented. But the proposed wearable antenna may be attached to human body, so the specific absorption ratio (SAR) must be calculated.
Abstract: In this paper, a novel multiband wearable fractal antenna suitable for GPS, WiMax and WiFi (Bluetooth) applications is presented. This antenna is designed to operate at four resonance frequencies are 1.57, 2.7, 3.4 and 5.3 GHz. The proposed wearable antenna may be attached to human body, so the specific absorption ratio (SAR) must be calculated. Therefore, another design to reduce SAR value with a spiral metamaterial meandered in the ground plane is introduced. In addition, a wearable fractal antenna system integrated on a life jacket is also presented.
TL;DR: In this article, the authors compared the performance of the FDTD and FIT methods in the near-field of a horizontal dipole antenna in terms of simulated current and electric field at different distances from the center of the antenna inside the half-space.
Abstract: In this paper we compare current implementations of commonly used numerical techniques - the Finite-Difference Time-Domain (FDTD) method, the Finite-Integration Technique (FIT), and Time-Domain Integral Equations (TDIE) - to solve the canonical problem of a horizontal dipole antenna radiating over lossless and lossy half-spaces. These types of environment are important starting points for simulating many Ground Penetrating Radar (GPR applications which operate in the near-field of the antenna, where the interaction among the antenna, the ground, and targets is important. We analysed the simulated current at the centre of the dipole antenna, as well as the electric field at different distances from the centre of the antenna inside the half-space. We observed that the results from the simulations using the FDTD and FIT methods agreed well with each other in all of the environments. Comparisons of the electric field showed that the TDIE technique agreed with the FDTD and FIT methods when observation distances were towards the far-field of the antenna but degraded closer to the antenna. These results provide evidence necessary to develop a hybridisation of current implementations of the FDTD and TDIE methods to capitalise on the strengths of each technique.
TL;DR: In this article, instead of using the Henyey-Greenstein (HG) phase function, the authors make use of the Petzold's measured data value of the scattering phase function in turbid sea water.
Abstract: In underwater wireless optical communication links, the suspended particles in the water can lead to multiple path transmission of the light, causing the temporal dispersion and attenuation of beam pulse. The scattering phase function is a key parameter to model angle scattering in the Monte Carlo simulation and can be approximated by the commonly used Henyey-Greenstein (HG) phase function, but in turbid sea water environment, the HG phase function cannot match well with the measured value of the particle phase function. In this work, instead of using the HG phase function, we make use of the Petzold’s measured data value of the scattering phase function in turbid sea water. We propose a numerical solution for the computing of the scattering angle based on the measured particle phase function and present the difference of effect on temporal dispersion between the measurement and HG phase function. Numerical results show that our model is more accurate than the widely used HG model. An analytic double Gamma function is used to fit the Monte Carlo simulation results, and a good fit is found between the double Gamma function and the Monte Carlo simulations.
TL;DR: In this article, two antennas with identical radiators on different substrates are designed and fabricated on polyamide and teslin paper substrates, deploying a modified rectangle-shaped radiator.
Abstract: Compact wideband flexible monopole antennas are designed and analyzed for its performance for Body Centric Wireless Communications (BCWC). Two antennas with identical radiators on different substrates are designed and fabricated on polyamide and teslin paper substrates, deploying a modified rectangle-shaped radiator. With the aid of modifications in the radiating plane and defecting the ground plane, the polyamide based antenna is designed to operate between 1.8 and 13.3 GHz, and teslin paper based antenna is designed to operate between 1.45 and 13.4 GHz to cover the wireless communication technology frequencies and ultra-wideband range for various wireless applications. The reflection coefficient characteristics of the fabricated antennas on free space and on various sites of the body are measured and match reasonably well with the simulated reflection coefficient characteristics. The specific absorption rate (SAR) analysis is also carried out by placing the antennas on tissue layered model.
TL;DR: In this article, a dual band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with uniform rejection performance was designed on an FR4 substrate.
Abstract: A compact dual band-notched ultra-wideband (UWB) multiple-input multiple-output (MIMO) antenna with uniform rejection performance is designed on an FR4 substrate (35 × 23 × 1.6 mm3). Compared with the existing UWB MIMO antennas, a second-order notched band with uniform performance for 5.15–5.825 GHz is achieved, which results from the interplay between a 1/3λ open-end slot and a 1/2λ parasitic strip. A 1/4λ open-end slot is also applied to the 3.3–3.7 GHz reject band. The two slots are connected at their open ends, that can help to get the uniform reject performance for 5.15–5.825 GHz and make the high cutoff frequency of the impedance matching band go toward the higher frequencies. Excluding the two rejected bands, a band with |S11| ≤ −10 dB, |S21| ≤ −17 dB and frequency ranged from 3.1 to 10.9 GHz is achieved, and results show that a uniform performance for 5.15–5.825 GHz is obtained.
TL;DR: In this paper, a material sample of Camphour Sulphonic Acid doped Polyaniline (PANI-CSA) was considered towards its conceivable use as a microwave shield.
Abstract: A material sample of Camphour Sulphonic Acid doped Polyaniline (PANI-CSA) is contemplated towards its conceivable use as a microwave shield. Shielding towards electromagnetic interferences (EMI) is measured over various frequency bands by the waveguide method. Plane wave electromagnetic theory is used to generalize the overall reflection and transmission coefficients of the polymer. EMI shielding of the polymer, in the form of Shielding Efficiency (SE), is analyzed over the microwave frequency range from 2 to 18 GHz, demonstrating the potential value of the polymer as an electromagnetic interference (EMI) shield for commercial purposes. The shielding film is fabricated using standard procedure with CSA as the dopant and m-cresol as the solvent. The shielding effectiveness as high as 45 dB for the sample of PANI doped with CSA is observed.
TL;DR: In this paper, a compact MIMO antenna resonating at multi-band of frequencies is proposed, where the edge to edge separation between two antennas is λ 0/31 and still maintains low mutual coupling levels between the two antennas.
Abstract: Abstract—Nowadays everyone needs electronic gadgets in compact size, and single device should accomplish all the tasks. A compact MIMO antenna resonating at multi-band of frequencies is proposed in the current research work. The proposed MIMO antenna consists of two elements. The edge to edge separation between the two antennas is λ0/31 and still maintains low mutual coupling levels between the two antennas. The proposed MIMO antenna resonates at 4.75 GHz, 5.89 GHz, 6.74 GHz, 8.25 GHz and 9.82 GHz. The mutual coupling is reduced by −23.78 dB at 4.75 GHz, −25.71 dB at 5.89 GHz, −29 dB at 6.74 GHz, −32.79 dB at 8.25 GHz and −21.5 dB at 9.82 GHz, respectively. The performance of the proposed MIMO system was evaluated in terms of S-parameters, Envelope Correlation Coefficient (ECC), Voltage Standing Wave Ratio (VSWR), and Radiation Pattern. The measured and simulated results are presented.
TL;DR: The results provide recommendations for partitioning data from a 3-D computational model to achieve the best GPU performance and compare the speedup using different numbers of GPUs.
Abstract: A parallel frequency-dependent, finite-difference time domain method is used to simulate electromagnetic waves propagating in dispersive media. The method is accomplished by using a singleprogram-multiple-data mode and tested on up to eight NVidia Tesla GPUs. The speedup using different numbers of GPUs is compared and presented in tables and graphics. The results provide recommendations for partitioning data from a 3-D computational model to achieve the best GPU performance.