13 research outputs found

    A Novel Wideband Bandpass Filter using H-shaped DGS

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    This paper presents a novel compact wide-band bandpass filter (BPF) having good selectivity. It is designed using a dual-plane structure which consists of a parallel-coupled microstrip line on the upper surface and three H-shape defected ground structures (DGS) on the ground plane. By adding three H-shape DGS units on the ground plane, then properly adjusting their dimensions and position, the bandwidth and selectivity of the designed filter can be significantly improved. A compact prototype of wide-band microstrip bandpass filter has been designed, fabricated and measured for the wireless systems applications. The filter exhibits a center frequency at 4.8 GHz, passband from 2.8 GHz to 6.8 GHz with best insertion loss and return loss of 0.8 dB and 40 dB, respectively. The measured results agrees well with the theoretical expectations validating the proposed design

    Proposal of MIMO Ultra-Wide Band Antenna with Low Mutual Coupling

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    In this paper, a new ultra-wide band (UWB) MIMO antenna is proposed. A MIMO antenna set consists of two single ultra-wide band antennas. This simple and compact MIMO antenna, which is designed to work from 3.1 GHz to 10.6 GHz, has a broad bandwidth with the VSWR ≤ 2. In addition, MIMO antenna characteristics such as radiation pattern, maximal gain are thoroughly investigated

    Using Solvent Vapor Annealing for the Enhancement of the Stability and Efficiency of Monolithic Hole-conductor-free Perovskite Solar Cells

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    In the last few years, perovskite solar cells have attracted enormous interest in the photovoltaic community due to their low cost of materials, tunable band gap, excellent photovoltaic properties and easy process ability at low temperature. In this work, we fabricated hole-conductor-free carbon-based perovskite solar cells with the monolithic structure: glass/FTO/bl-TiO2_{2}/(mp-TiO2_{2}/mp-ZrO2_{2}/mp-carbon) perovskite. The mixed 2D/3D perovskite precursor solution composed of PbI2_{2}, methylammonium iodide (MAI), and 5-ammoniumvaleric acid iodide (5-AVAI) was drop-casted through triple mesoporous TiO2_{2}/ZrO2_{2}/carbon electrode films. We found that the isopropyl alcohol (IPA) solvent vapor annealing strongly influenced on the growth of mixed 2D/3D perovskite on triple mesoscopic layers. It resulted in the better pore filling, better crystalline quality of perovskite layer, thus the improved stability and efficiency of perovskite solar cell was attributed to lower defect concentration and reduced recombination

    Structure and Electrochemical Impedance of LiNix_{x}Mn2−x_{2 - x}O4_{4}

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    Ni-substitution spinel LiNixMn2−xO4 (x = 0, 0.1, 0.2) materials were synthesized by the sol--gel method. The structure and  morphology of the samples were characterized by the X-ray diffraction (XRD)  and the scanning electron microscopy. The ac conduction of the materials was  investigated by electrochemical impedance spectroscopy (EIS) measurements.  The refinement results showed that the substitution of Ni decreased the  lattice constant and Mn--O distance, while increased Li--O bond length and  16c octahedral volume. The EIS results confirmed the decrease of  conductivity with increasing Ni substitution content. Based on XRD and EIS  results, the relationship between the crystal structure and electrochemical  behavior of the materials was discussed and explained

    An approach for block transmission based precoding and equalisation with improved performance

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    Block transmission is very efficient method to combat with inter-symbol interference. However, the way it uses the guard intervals reduces spectral efficiency of the system. In this paper, we propose a new approach to block transmission based precoding and equalisation for frequency selective channels. Different with standard block transmission schemes, our method employs redundancy in a different way so that the channel energy can be better employed, thus leading to improved performance under the same code rate

    Broadband SVD and non-linear precoding applied to broadband MIMO channels

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    We address the problem of precoding and equalisation of broadband MIMO systems. A new non-block based methods is based on a broadband singular value decomposition, which can decouple a broadband MIMO channel into independent dispersive SISO subchannels. We thereafter apply Tomlinson-Harashima precoding to mitigate the dispersiveness of these SISO subchannels. We present arguments why this is a suitable approach compared to existing methods, underlined by some simulation results

    PCA-Aided Linear Precoding in Massive MIMO Systems with Imperfect CSI

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    In this paper, a low-complexity linear precoding algorithm based on the principal component analysis technique in combination with the conventional linear precoders, called Principal Component Analysis Linear Precoder (PCA-LP), is proposed for massive MIMO systems. The proposed precoder consists of two components: the first one minimizes the interferences among neighboring users and the second one improves the system performance by utilizing the Principal Component Analysis (PCA) technique. Numerical and simulation results show that the proposed precoder has remarkably lower computational complexity than its low-complexity lattice reduction-aided regularized block diagonalization using zero forcing precoding (LC-RBD-LR-ZF) and lower computational complexity than the PCA-aided Minimum Mean Square Error combination with Block Diagonalization (PCA-MMSE-BD) counterparts while its bit error rate (BER) performance is comparable to those of the LC-RBD-LR-ZF and PCA-MMSE-BD ones

    Effects of Mulberry Pomace Addition and Transglutaminase Treatment on the Quality of Pasta Enriched with Antioxidants and Dietary Fiber

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    Mulberry pomace powder, a by-product of mulberry juice processing, was added to pasta recipe to make pasta with high dietary fiber and antioxidant contents. The effects of mulberry pomace ratio on the nutritional, textural and cooking properties as well as the sensory overall acceptance of the product were investigated. A significant increment in dietary fiber and total anthocyanin contents as well as decrement in cooking quality, texture and color change were observed. The cooking loss increased with the substitution level of mulberry pomace while the optimal cooking time, swelling index and water absorption index decreased. The quality improvement of 10% mulberry pomace fortified pasta was investigated by adding a transglutaminase preparation with enzyme dosage from 0.25 to 1.00 U/g protein. The fortified pasta treated with transglutaminase at 0.50 U/g protein showed a significant improvement in chewiness, tensile strength and elongation rate but was not significantly affected in terms of the swelling index and water absorption. The use of transglutaminase also improved the overall acceptability of the fortified pasta. Mulberry pomace powder may, therefore, be considered a potential antioxidant-rich and dietary fiber-rich material for incorporation into pasta products
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