Beam Tilting Antenna Using Integrated Metamaterial Loading

Abstract

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.

Improvement of Gain and Elevation Tilt Angle Using Metamaterial Loading for Millimeter-Wave Applications

“…The drawback of this configuration is its large physical size, i.e., , as it requires two lines of 26-element linear array and its sidelobe is 5 dB. Authors in [6] have demonstrated the beam-tilting phenomenon can be realized using high refractive-index metamaterial loading that is integrated within the antenna structure.…”

“…2, is employed. This is a modified version of the H-shaped meandered-line metamaterial structure in [6]. The unit cell is constructed on a Rogers RT5880 substrate with the thickness ( ) of 0.508 mm, permittivity ( ) of 2.3, and loss tangent of 0.0009.…”

Beam Focusing Compact Wideband Antenna Loaded With Mu-Negative Metamaterial for Wireless Lan Application

“…It is widely used in different applications areas, such as sensors [4,5], energy harvesting [6], wave polarization [7,8], and controllable absorber [9]. It is also used for antennas performance enhancement, such as radiation enhancement [10], multi-directional beam generation [11], beam tilting [12][13][14], gain enhancement [15,17], bandwidth enhancement [15], directivity [16], and multiband operation [18]. In [4], a circular split ring resonator based on metamaterial, used for fluid, strain and rotation sensing applications.…”

“…A pattern controlled frequency tunable microstrip antenna loaded with multiple split ring resonators using RF MEMS switches is presented to control the direction of the major lobe of the radiation pattern [12]. In [13], it is investigated that the integrated metamaterial loaded in a planar antenna can deflect the beam of an end-fire antenna by 17 • with respect to the end-fire direction in the frequency range of 7.3-7.5 GHz. An electronic bandgap structure integrated with the orthogonal plane of a dipole antenna [14] is presented for tilting the beam about 28 • at 3.5 GHz.…”

Beam-Deflection Using Gradient Refractive-Index Media for 60-GHz End-Fire Antenna

“…More recently, the authors in [10] integrated a 4×3 array of high refractive-index metamaterial unit-cells with a bow-tie antenna to demonstrate the feasibility of tilting the direction of the antenna main beam for C-band applications; however the refractive index of the unit-cell could not be altered. With this technique, the antenna exhibits again enhancement of 1.5-2.5 dBi over the frequency range of 7.3-7.7 GHz but the angle of the main beam is limited to 17 o .The authors in [11] presented passive fixed beam forming network (BFN) by applying a 4×4 Butler matrix consisting a SIW phase shifter and coupler to tilt the main beam in both E-and H-planes by 20 o .…”