Planar Wideband Polarization Diversity Antenna for Mobile Terminals

This letter presents a planar wideband polarization diversity antenna for mobile terminals. The antenna consists of two orthogonally oriented quasi-complementary antennas (QCA) formed by the combination of an electric dipole and a magnetic slot and located at the separate ends of a mobile ground plane. The studies with a single quasi-complementary antenna element show that the electric dipole and the magnetic slot are partly compensating each other providing large bandwidth and offering good radiation properties. The measured -6-dB impedance bandwidth of the individual QCA is from 1.8 to 4.6 GHz, corresponding to an 87.5% relative bandwidth. The measured
S
₂₁
is less than - 18 dB within the - 6-dB impedance bandwidth. The average measured total efficiency at the aforementioned bandwidth is - 0.95 dB. The measured radiation patterns are presented at 2 and 4 GHz with orthogonal polarizations. Finally, the measured envelope correlation and effective diversity gain (EDG) as a function of frequency are presented, with a maximum correlation less than 0.01 and EDG better than 8.0 dB.