Beamforming Radiation Properties of Absorbing/Transparent Zones-Added Horn Antenna

Abstract

In this study, we present beamforming of radiation patterns on a transmitter horn antenna bymounting an electromagnetic wave absorber, in which electromagnetic wave absorber isfabricated as concentric zones. The concentric zones consist of an absorbing material ofmanganese soft spinel ferrite blended with multi-walled carbon nanotubes with the thickness of1 mm installed on the aperture of the antenna working in Ku-band. We have experimentallymeasured scattering parameter of transmission, S21, using a vector network analyser to performradiation patterns in polar coordinates. As compared to the radiation properties of air horn antennaand absorbing/transparent zone-added horn antenna produces an appreciable effect to concentrateradiation beam in the main, side and back lobes with reducing side and back lobe levels for eachfrequency in H-plane. For the radiation pattern in E-plane, we have observed the suppressed sidelobes at three frequencies of 15 GHz, 17 GHz and 18 GHz. The results indicate that theabsorbing/transparent zone keeps an important role for further development of the applications ofdirectional antennas so that the effective radiation is to be significantly concentrated