Improved Planar Wideband Antenna Element and its Usage in a Mobile MIMO System

A simple antenna structure for a multiple-input-multiple-output (MIMO) system in a mobile terminal with spatial diversity is presented. A single antenna element consists of a combination of an electric dipole and a square magnetic slot. The studies with a single quasi-complementary antenna element show that the electric dipole and the square-shaped magnetic slot are partially compensating the effect of the electric conductor closely spaced to the electric dipole (0.0037-0.01¿). Simulations also show that by scaling antenna structure, a 0.7-2.1-GHz frequency bandwidth can be achieved. The measured -6-dB impedance bandwidth of the MIMO antenna prototype is from 2.0 to 5.6 GHz, corresponding to a 95% relative bandwidth. The measured S 21 is less than -19 dB within the -6-dB impedance bandwidth. The average measured total efficiency at the aforementioned bandwidth is -0.85 dB. The measured radiation patterns are presented at 2 and 5 GHz with a maximum total gain of 2.8 and 5.7 dBi, respectively. The measured envelope correlation of the MIMO antenna is less than 0.04 with 90% MIMO efficiency within the -6-dB impedance bandwidth. © 2002-2011 IEEE.This work was supported by the Finnish Funding Agency for Technology and Innovation, Nokia Devices Oulu, Pulse Finland, and Universitat Politecnica de Valencia under Project PAID-06-09-2868. The work of M. Sonkki was supported by the Tauno Tonning Foundation and Universitat Politecnica de Valencia.Sonkki, M.; Antonino Daviu, E.; Cabedo Fabrés, M.; Ferrando Bataller, M.; Salonen, E. (2012). Improved Planar Wideband Antenna Element and its Usage in a Mobile MIMO System. IEEE Antennas and Wireless Propagation Letters. 11:826-829. https://doi.org/10.1109/LAWP.2012.2208615S8268291