Very-Wide-Band Six-Port Single-Patch Antenna With Six Uncorrelated Waves for MIMO Access Points

A very-wide-band six-port circular patch antenna for MIMO access-point application is presented. The six-port patch antenna can radiate six uncorrelated waves (envelope correlation coefficients < 0.01) in a very wide band of about 3.1-7.2 GHz (fractional bandwidth about 80%), which can be applied to cover 3.3-5.0 GHz for 5G communication and 6.425-7.125 GHz for possible new mobile band. The six uncorrelated waves are generated by using six coupling L-strip feeds to respectively excite six 60 degrees-resonant sectors isolated by six radial shorting metal walls connecting the circular patch to the ground plane. Enhanced port isolation (>20 dB) is obtained by embedding six decoupling radial slots along the centerlines of the six 60 degrees-resonant sectors, with very small effects on the excited resonant modes. Details of the proposed six-port six-uncorrelated-wave single-patch MIMO antenna are addressed. Experimental results of the fabricated prototype are presented.