Yazarlar
- Teber, Ahmet(2)
Yayınlar
- MakaleAçık Erişim2020Scopus SJRQ3Beamforming radiation properties of absorbing/transparent zones-added horn antenna
Teber, Ahmet
In this study, we present beamforming of radiation patterns on a transmitter horn antenna by mounting an electromagnetic wave absorber, in which electromagnetic wave absorber is fabricated as concentric zones. The concentric zones consist of an absorbing material of manganese soft spinel ferrite blended with multi-walled carbon nanotubes with the thickness of 1 mm installed on the aperture of the antenna working in Ku-band. We have experimentally measured scattering parameter of transmission, S21, using a vector network analyser to perform radiation patterns in polar coordinates. As compared to the radiation properties of air horn antenna and absorbing/transparent zone-added horn antenna produces an appreciable effect to concentrate radiation beam in the main, side and back lobes with reducing side and back lobe levels for each frequency in H-plane. For the radiation pattern in E-plane, we have observed the suppressed side lobes at three frequencies of 15 GHz, 17 GHz and 18 GHz. The results indicate that the absorbing/transparent zone keeps an important role for further development of the applications of directional antennas so that the effective radiation is to be significantly concentrated.
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İncele - MakaleAçık Erişim2020Investigation of Beam Width Shaping of a Ku-band Horn Antenna using a Diffractive Optic Element and an Electromagnetic Wave Absorber
Teber, Ahmet
The feasibility of beam-shaping of a Ku-Band horn as a transmitting (Tx) antenna by mounting two different versions of lenses which are kind of Fresnel Zone Plates (FZP) is studied. The designed and fabricated geometrical structures offer a simpler approach building Fresnel Zone Plates by using an electromagnetic wave absorber and diffractive optic material. The diffractive optic material, paraffin, forms a set of alternating open and opaque annular zones on a flat surface, based on the design principles of Fresnel Zone Plates. An electromagnetic wave absorber covers the top surface of the formed paraffin, but not including the grooves. Thereafter, the Fresnel Zone plates are suitably attached in front of the transmitter horn antenna, located in the far-field region of a receiving antenna. The half-power beam-widths for the horn antenna (unloaded) and with two types of lenses are investigated. The results indicate that Fresnel zone plate structures can play a role suppressing side lobes in H-plane so that the effective radiation is to be significantly concentrated.
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