Concurrent 2.4/5-GHz multi-loop MIMO antennas with wide 3-dB beamwidth radiation for access-point applications

A high-gain, wide-beamwidth, six-loop-antenna MIMO system suited for wireless access points in the concurrent WLAN 2.4 and 5 GHz bands is presented. The antenna system mainly comprises an antenna ground plane and single-band loop antennas, among which the three antennas are designated for 2.4 and 5 GHz operation respectively. The antennas are set in a sequential, rotating arrangement on the ground plane with an equal inclination angle of 60° to form a symmetrical structure, and the 2.4 and 5 GHz loops are facing each other one by one. The experimental results show that good port isolation can be obtained between antenna ports. High-gain, directional radiation patterns with wide 3-dB beamwidth in elevation planes are also observed. Details of a design prototype are described and discussed in the paper.