Twelve port MIMO antenna with polarisation diversity for cognitive radio applications

Abstract

In this letter, to overcome the drawbacks in reconfigurable antennas and maintain all the advantages in planar antennas, a compact 12 port integrated UWB and narrow band (NB)/wideband antennas for cognitive radio MIMO applications with polarisation diversity is presented. The proposed system has one pair of UWB antennas for sensing the spectrum and five pairs of NB/wideband antennas for communication. Each pair has two identical antennas, which are orthogonal to each other for polarisation diversity. Sensing antennas linked with ports (P1 and P7) have operating bandwidth of 3-11 GHz, whereas the antennas linked with ports (P2 and P8), (P3 and P9), (P4 and P10), (P5 and P11), and (P6 and P12) have operating bandwidths of 3.5-5.8 GHz, 2.8-3.5 GHz and 5.6-8 GHz (dual band), 8-8.4 GHz and 9-9.8 GHz (dual band), 8.4-9 GHz, and 9.8-11 GHz, respectively. Moreover, the overall volume of the antenna is 58mm × 50mm × 1.6 mm and the entire UWB spectrum is covered by NB/wideband antennas. Also, without any decoupling network, isolation of better than 20 and 15 dB is achieved between every two identical and nonidentical antennas, respectively.