One- and Two-Dimensional Beam-Switching Antenna for Millimeter-Wave MIMO Applications

One- (1-D) and two-dimensional (2-D) beamforming is presented for a planar dipole antenna operating at millimeterwave bands. 1-D beamforming was achieved by using mu (μ) -near-zero (MNZ) metamaterial slabs that were integrated in the dipole antenna, where each slab was loaded with an array of low refractive-index unit-cells. The resulting radiated beam can be scanned by 35° due to the phase shift in the beam introduced by its interaction with the metamaterial slabs. In addition, the proposed antenna configuration provides gain improvement of 8 dB as the slabs effectively increase the aperture size of the antenna. An array of MNZ inclusions in the E-plane of a double dipole antenna is shown to provide scanning from -35° to +35° with respect to the end-fire direction over 57-64 GHz. 2-D beam-scanning was realized by increasing the number of MNZ unit-cells in the elevation plane of double dipole antenna. Loading the slabs in front of the double dipole antenna with 10 × 7 array of MNZ unit-cells is shown to provide a beam deflection of 35° in both the azimuth and elevation planes.