567 research outputs found

    Design of Serial-Fed Bend-Array and Measured Results

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    For the next generation mobile system (5G), a cylindrical lens antenna is developed for mobile base station application. As for the feed radiator for this lens antenna, bendarray configuration that produces a bifurcated beam is also developed. The bend-array configuration consisting of four rectangular patch array elements with serial feed network. In previous work, achievement of the bifurcated beam by bendarray configuration was shown by electromagnetic simulations. In this paper, a practical bend-array composed of four numbers of patch elements is fabricated. To verify the radiation characteristics, measured results of antenna input characteristic and radiation pattern are compared with the designed results. Through good agreement of measured and designed results, achievement of practical antenna is ensured

    A novel green antenna phase-shift system with data acquisition boards

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    A novel green phase shifter system is proposed in this research. The system is developed by a combination of reconfigurable beam steering antennas and data acquisition (DAQ) boards. A combination of two reconfigurable beam steering antennas, located side-by-side, forms a spatial configuration structure with a fabricated ‘green’ element plank of rice husk placed in between. The concept of a spatial configuration technique has been ‘mutated’ by shifting the structure of spiral feed line and aperture slots of first beam steering antenna by as much as 45 ◦ . The PIN diode switches connected to the DAQ boards enable the intelligent capability of the spatial antennas. The activation of certain degree radiation patterns of either the first beam steering antenna or the second beam steering antenna depends on the memory of the DAQ boards — Beam Manager. When an intruder comes from the cardinal angles of 0◦/ 360◦, 90◦, 180◦, or 270◦, its range and angles’ location will be automatically detected by the first antenna through the output ports of the 1st DAQ: P1.0, P1.1, P1.2, and P1.3. The second antenna is then activated by the output ports of the 2nd DAQ: P2.0 up to P2.3, to adaptively maneuver the beam towards four different ordinal directions of 45◦, 135◦, 225◦, and 315◦

    Reason Maintenance in Product Modelling via Open Source CAD System

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    The present and future challenges of a new product design, forecasting and risk management launch strategy for a new product modelling decision process. This paper intends to propose and to look towards the development of a low-cost integrated CAD-CAPP-CAD/CAM product modelling system for the design and manufacture of a proposed product. It is a mapping between several design phases like functional design, technical design and physical design. The modelling data generation process begins with the drafting of a product to be maintained using the drafting software package. From the CAD drawing, the data are transferred to be used as the product models and a CAPP software package will then prepare the operational parameters for the manufacturing of the product. These process data are relayed to a CAM software package, which will then generate the automating information processing functions. The final stage of the function is to support design and manufacturing operations that may have reaped many benefits in terms of its initial equipment and software costs

    VULNERABILITY MAPPING AND ANALYSIS: AN IMPLEMENTATION IN GEOHAZARD AREAS IN SABAH

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    Vulnerability identifies the element-at-risk as well as the evaluation of their relationships with the hazard. The relationships relate the landslide potential damages over a specific element-at-risk. Vulnerability can be defined as the degree of loss to a given element-at-risk or set of elements at risk resulting from the occurrence of a natural phenomenon of a given magnitude and expressed on a scale from 0 (no damage) to 1 (total damage). In this study, the landslide vulnerability mapping and analysis were made on two element-at-risks namely buildings and roads. Based on field observations, building and road construction materials have been classified into 22 and 5 construction materials respectively. The field visits were made on specific areas based on candidate buildings and roads as chosen during the landslide exposure analysis and mapping. The vulnerability values for these element-at-risks were expressed using expert opinion. Four experts have been interviewed with separate sessions. The experts were also supplied with local information on the landslides occurrences and photos of element-at-risk in Kundasang and Kota Kinabalu. The vulnerability matrices were combined based on the weighted average approach, in which higher weight was assigned to panel with local expert (landslides and damage assessment), wide experience in landslide vulnerability analysis, hazard and risk mapping. Finally, the vulnerability maps were produced for Kundasang and Kota Kinabalu with spatial resolution of 25 cm. These maps were used for the next step i.e. landslide risk mapping and analysis

    MAPPING OF HIGHLY HETEROGENEOUS URBAN STRUCTURE TYPE FOR FLOOD VULNERABILITY ASSESSMENT

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    Vulnerability plays an important role in risk assessment. For flood vulnerability assessment, the map and characteristics of elements-at-risk at different scales are strongly required depending on the risk and vulnerability assessment requirements. This study proposes a methodology to classify urban structure type by combining object-based image classification and different high resolution remote sensing data. In this study, a high resolution satellite image and LiDAR have been acquired over Kota Bharu, Kelantan which consists of highly heterogeneous urban structure type (UST) classes. The first stage is data pre-processing that includes orthorectification and pansharpening of Geoeye satellite image, image resampling for normalised Digital Surface Model (nDSM) and followed by image segmentation for creating meaningful objects. The second stage comprises of derivation of image features, generation of training and testing datasets, and classification of UST. The classification was based on three types of machine learning classifiers, i.e. Random Forest (RF), Support Vector Machine (SVM) and Classification and Regression Tree (CART). The results obtained from the classification processes were compared using individual omission and commission error, overcall accuracy and Kappa coefficient. The results show that Random Forest classifier with all image features achieved the highest overall accuracy (93.5%) and Kappa coefficient (0.94). This is followed by CART classifier with overall accuracy of 93.7% and Kappa coefficient of 0.92. Finally, SVM classifier produced the lowest overall accuracy and Kappa coefficient with 88.6% and 0.86, respectively. The UST classification result can be further used to assist detailed building characterisation for large scale flood vulnerability assessment

    Characterization of Lens Antenna in Wireless Communication System

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    The focus of this paper is to design lens and analyze the lens behavior in lens antenna. This lens antenna is designed to enhance the gain of conventional antenna. A few factors that influenced the design of lens and gain of lens antenna is investigated. CST software is used to design the lens. At the end of this experiment, the lens gain increased from 8.782 dB to 11.07 dB

    Multiwavelength Brillouin fiber laser with enhanced reverse-S-shaped feedback coupling assisted by out-of-cavity optical amplifier.

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    A multiwavelength widely tunable Brillouin optical comb with an enhanced reverse-S-shaped feedback coupling assisted by out-of-cavity optical amplifier is demonstrated. The enhancement is done by locating the amplifier and the Brillouin pump into the reverse-S-shaped fiber section. The oscillating modes in the cavity are directly influenced solely by the Brillouin gain. A wide tuning range of 45 nm is obtained that is only limited by the erbium amplification bandwidth. An average of eleven laser lines that can be tuned to over 45 nm wavelengths is obtained at 40% optimum output coupling ratio

    COPPER LAYER SHEET RESISTANCE EVOLUTION AS A FUNCTION OF POST-SEED PROCESS SELF-ANNEALING TIME

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    Copper layer metallization is one of the important processes in integrated circuit manufacturing.  One of the issues faced in this process is the proneness of Cu interface diffusion as well as surface oxidation which degrade some of the Cu thin film properties. Due to this concern, most integrated circuit manufacturing facility imposed 12 hours maximum delay time between the Cu seed deposition and   Cu electroplating step. However, there is lack of study and data to justify support this time restriction.  This study investigated the effect of self-annealing time between Cu seeding process and Cu electroplating process to the sheet resistance, reflectance, and stress of the deposited film. The data indicated that the there is no significant deterioration or fluctuation in sheet resistance, reflectance, and stress beyond 12 hours delay time.  This suggested that the imposed 12 hours maximum delay time between Cu seed and Cu electroplating process can be further extended, which will give greater flexibility for the manufacturing scheduling
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