Investigation of anisotropic negative permeability medium cover for patch antenna

A more directional and higher gain patch antenna with an anisotropic negative permeability medium (NPM) cover is proposed. The patch antenna operates at the frequency where the permeability of split-ring resonator (SRR) is negative, and then the sideward radiation can be forbidden. It leads to a significant enhancement of designing the high gain antenna. We investigate numerically and experimentally the performance of the antenna when NPM composed of SRR is placed above the patch antenna. The measured result has a good agreement with the simulation. Compared with the conventional antenna, the result shows that the beam of antenna with the NPM cover becomes more convergent, half-power beamwidth is smaller by almost 30deg in the H-plane and 10deg in the E-plane and the gain is higher by 4.03 dB. Moreover, NPM cover can have applications in the other types of antenna such as monopoles, dipole antennas, leak-wave antennas and aperture antennas.