Browsing by Subject "Radiation patterns"

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    Calculation of radome-enclosed aperture antenna in 3-D
    (IEEE, 2010-09) Sukharevsky, I.; Altintas, Ayhan
    The exact mathematical model of an aperture antenna and the image theory are used to develop exact and PO integral representations of the fields radiated by radome-enclosed aperture antenna. The desired problem is reduced to finding fields of a plane wave diffracted on the "symmetrized" radome. The passage of the wave through the wall of the radome is analysed by means of geometrical optics. Caustic influence is taken into account, and the contribution of stationary phase points of reflected field to the far-side radiation is discussed. Radiation patterns for antennas with a specified ampliphase distribution enclosed in spherical and parabolic radomes are analysed. © 2010 IEEE.
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    Decoupling of multifrequency dipole antenna arrays for microwave imaging applications
    (Hindawi Publishing Corporation, 2010) Saenz, E.; Guven, K.; Özbay, Ekmel; Ederra, I.; Gonzalo, R.
    The mutual coupling between elements of a multifrequency dipole antenna array is experimentally investigated by S -parameter measurements and planar near-field scanning of the radiated field. A multifrequency array with six dipoles is analyzed. In order to reduce the coupling between dipoles, a planar metasurface is placed atop the array acting as superstrate. The mutual coupling of the antenna elements in the absence and presence of the superstrate is presented comparatively. Between 3 and 20dB mutual coupling reduction is achieved when the superstrate is used. By scanning the field radiated by the antennas and far-field measurements of the radiation pattern, it is observed that the superstrate confines the radiated power, increases the boresight radiation, and reduces the endfire radiation.
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    ItemOpen Access
    Effect of the off-focus shift of the feed on the radiation characteristics of a 2-D parabolic reflector antenna
    (IEEE, 2010) Oğuzer, T.; Altıntaş, A.; Nosich, Alexander
    The parabolic reflector antennas are widely used in the telecommunication systems and generally have large aperture sizes like 50λ to 80λ and larger. Their reliable full-wave analysis with the conventional Method of Moments (MoM) or with the other numerical methods is difficult because of inaccessible speed and accuracy. This statement is valid both for 3D and 2D reflector antennas in both polarizations. The Method of Analytical Regularization (MAR) constitutes an alternative solution compared to the ordinary MoM, which can provide only 1-2 digit accuracy. It provides finer accuracy within a reasonable computation time because the computational error can be decreased simply by increasing the matrix size in MAR. We have previously developed this method for the accurate simulation of the arbitrary conical section profile 2D reflector antennas, and the corresponding codes have provided us with accurate benchmark data. Here we study a similar problem however with the feed simulated by Complex Source Point (CSP) source located at an off-focus point on the symmetry axis of a front-fed reflector antenna. The numerical results are presented for the radiation characteristics including the forward and backward directivities and the radiation patterns in all directions. © 2010 IEEE.