31 research outputs found

    Self-Casing Low-Cost Reflectarray With a Single Porous Layer

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    A self-casing Microstrip Reflectarray Antenna (MRA) is proposed with high-gain, broadband, mechanically simple properties. It needs no radome due to exploiting a low-cost porous superstrate. Such an inhomogeneous layer is made up of the robust FR4 dielectric in which air rods are periodically drilled. This porous layer is suspended above the metallic plane using spacer and the re-radiating elements are printed on its interior side for designing a broadband center-fed MRA. Its element is a new Butterfly-Like Patch (BLP) with two degrees of freedom (length and angle). By analyzing its sub-wavelength unit cell, the calculated total phase range is more than 700°, which can be a good choice for broadband MRA design. Using this phase response and an efficient phase synthesis technique, an optimized metallization arrangement is analytically obtained to design a good frequency behavior MRA. To validate the numerical results, a 270×270×3.9270\times 270\times 3.9 mm3 MRA with focal length 26.1 cm is manufactured and tested. Measured results show a peak gain 29.1dB with a 1-dB gain bandwidth of 42.6% ( 9.714.99.7\sim 14.9 GHz) and maximum efficiency 58% at central frequency 12GHz. It is experimentally shown that the gain and bandwidth of this self-covering MRA is better than conventional one

    Scattering Analysis of Periodic Thin Film Sandwiched by Plasmonic Nano-antenna Gratings

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    The role of predicting the formation of workaholism based on personality factors and perfectionism in academics

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    Objective: This study aims to determine the role of personality factors and perfectionism in predicting workaholism among the faculty members. Methods: The design of the study was correlational and the statistical population included faculty members of Islamic Azad University of East Azarbaijan Province, where 278 persons were selected among them using multistage cluster sampling method. The data were collected using a questionnaire on demographic and occupational characteristics, NEO five-factor inventory, and workaholism risk inventory and were analyzed using Pearson correlation coefficients and hierarchical regression analysis. Results: The results of regression analysis showed that by controlling demographic and occupational characteristics, personality factors of conscientiousness (β = 0.52), neurosis (β = −0.38), extraversion (β = 0.23), openness (β = 0.18) and perfectionism (β = 0.43) were able to predict 43% of the workaholism variance among the faculty members. Conclusions: According to the results of this study, personality factors can predict workaholism among university faculty members

    Design and Fabrication of an Efficient Metallic Phased Array for TACAN Application

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    Ungrounded composite right-/left-handed metamaterials: design, synthesis and applications

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