Pattern Diversity and Polarization Diversity Wide Band Circularly Polarized MIMO Antenna

This paper presents pattern and polarization diversity, planar wideband circularly polarized (CP) Multiple-Input and Multiple-Output (MIMO) antenna. 3dB axial ratio bandwidth (ARBW) is 2.45 GHz (8.11–10.56) while its impedance matching bandwidth (IMBW) is 3.52 GHz(8.07–11.59). Proposed antenna structure is simple and useful for X-band communication, and it has both pattern diversity and polarization diversity within the entire axial ratio band. The isolation between the antennas without using decoupling mechanism are high or better than -20dB within the entire impedance matching and axial ratio band. The antenna structure has been fabricated on FR-4 substrate and its simulated and measured results are in good agreement, which verify the design concept.