This communication presents a technique to redirect the radiation beam from a planar antenna in a specific direction with the inclusion of metamaterial loading. The beam-tilting approach described here uses the phenomenon based on phase change resulting from an EM wave entering a medium of different refractive index. The metamaterial H-shaped unit-cell structure is configured to provide a high refractive index which was used to implement beam tilting in a bow-tie antenna. The fabricated unit-cell was first characterized by measuring its S-parameters. Hence, a two dimensional array was constructed using the proposed unit-cell to create a region of high refractive index which was implemented in the vicinity bow-tie structure to realize beam-tilting. The simulation and experimental results show that the main beam of the antenna in the E-plane is tilted by 17 degrees with respect to the end-fire direction at 7.3, 7.5, and 7.7 GHz. Results also show unlike conventional beam-tilting antennas, no gain drop is observed when the beam is tilted; in fact there is a gain enhancement of 2.73 dB compared to the original bow-tie antenna at 7.5 GHz. The reflection-coefficient of the antenna remains dB in the frequency range of operation.
Abstract-An effective technique for reducing the mutual coupling between two Dielectric Resonator Antennas (DRA) operating at 60 GHz bands is presented. This is achieved by incorporating a metasurface between the two DRAs, which are arranged in the Hplane. The metasurface comprises an array of unique split-ring resonator (SRR) cells that are integrated along the E-plane. The SRR configuration is designed to provide band-stop functionality within the antenna bandwidth. By loading the DRA with 1×7 array of SRR unit cells, a 28 dB reduction in the mutual coupling level is achieved without compromising the antenna performance. The measured isolation of the prototype antenna varies from -30 to -46.5 dB over 59.3-64.8 GHz. The corresponding reflection coefficient of the DRA is better than -10 dB over 56.6-64.8 GHz.
Abstract-This paper presents a high gain bow-tie antenna that operates across 57 GHz-64 GHz for application in high data rate point-to-point communication systems. The proposed antenna consists of a pair of bow-tie radiators, where each radiator is etched on the opposite side of the common dielectric substrate and fed through substrate integrated waveguide (SIW) feed-line. The bow-tie radiators are arranged to cross each other symmetrically by tilting the feed-lines by 30 degrees in order to enhance the antenna gain and to obtain the required radiation pattern. The antenna is loaded with a pair of double G-shaped resonators (DGR) that are located in a region between the radiators and SIW in order to suppress the back-lobe level in the H-plane. Embedded in the E-plane of the antenna is an array of zero-index metamaterial (ZIM) unit-cells whose purpose is to effectively confine the electromagnetic waves in the end-fire direction in order to enhance its gain performance. A prototype antenna was fabricated and its performance was measured to validate the simulation results. The proposed structure exhibits a gain of 11.8-12.5 dBi over the frequency range of 57 GHz-64 GHz with reflection-coefficient less than -11 dB. In addition, the proposed antenna exhibits good cross-polarization which is less than -17 dB in both E-and H-planes at 60 GHz.IndexTerms-Millimeter-wave antenna, zero-index metamaterial, bow-tie antenna, end-fire antenna.
Abstract-1D and 2D-beamforming is presented for a planar dipole antenna operating at millimeter-wave bands. 1D-beamforming was achieved by using mu-near-zero (
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