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

Elevation-plane beam tilting is demonstrated for a printed dipole antenna operating over 57-64 GHz. This is achieved using a 3 ×4 array of high refractive-index metamaterial (HRIM) unit cells. The unit cell comprises a modified H-shaped structure with stub loading to control the refractive index of the unit cell over a finite frequency range. Integration of the 3 ×4 array in the H-plane of a dipole antenna is shown to deflect the main beam by + 30°with respect to the endfire direction over 57-64 GHz. In addition, the proposed technique provides 5 dB gain enhancement.