Circularly Polarized MIMO Dielectric Resonator Antenna With Reduced Mutual Coupling

A circularly polarized (CP) multiple-input-multiple-output (MIMO) antenna is investigated. This MIMO antenna consists of two identical dielectric resonator antennas (DRAs), which use the same feeding cross slots to generate the same CP fields. Four metal strips are printed on the lateral sides of each DRA to change the rotation direction of the E-field coupled in the passive (coupled) DRA, vary its polarization property, and thus make it opposite (orthogonal) to that of the active (driven) DRA. Thanks to the polarization orthogonality, the isolation between the two CP DRAs is improved significantly, without occupying extra space and destroying the antenna performance. In addition, using this decoupling scheme, the two CP DRAs can operate not only separately but also simultaneously. For verification, a prototype operating at the 2.4 GHz WLAN band is fabricated and measured. In the operating band (2.38-2.52 GHz), the MIMO antenna obtains a maximum improvement of 31 dB and an average improvement of 11 dB in isolation, at a center-to-center distance of 0.4λ
₀
.