Metamaterial-based electric and magnetic loop antennas with polarization diversity

In order to reduce correlation between multiple antennas and enhance spatial efficiency, novel polarization diversity antennas based on metamaterials are proposed by overlapping two antennas; an electric loop antenna and a magnetic loop antenna. The electrical loop antenna is realized by a resonant wire antenna, while the magnetic loop antenna is realized by an open-ended CRLH TL with a metamaterial concept. Since the current distributions of two antennas are orthogonal each other, each one independently operates with polarization diversity, which leads to minimize correlation. The proposed antennas can produce maximum spatial efficiency by overlapping two antenna elements. In order to place the magnetic loop antenna inside the electric loop antenna, the magnetic loop antenna´s size needs to be much smaller than 0.25 ¿ × 0.25 ¿, and thus spiral slots on the ground plane is used to reduce the size of magnetic loop antenna.