A Novel Compact Polarization Diversity Ultra-Wideband MIMO Antenna

A very compact modified simple structure Ultra-Wideband (UWB) antenna with a size of 18 mm by 30 mm is presented for polarization diversity applications. The antenna employs two orthogonal monopole antenna to achieve polarization diversity over the UWB. The antenna was fabricated to study the performance such as S-parameters, radiation pattern, radiation efficiency, peak gain, envelope correlation coefficient and group delay. The measured results demonstrated that the proposed antenna has not only UWB (147.96% impedance bandwidth) but also good isolation less than about -25 dB. Moreover, the system fidelity factor is sufficient for pulse transmission with average 89.6% and 85.3% for ports 1 and 2, respectively. Furthermore, a low envelope correlation coefficient of less than 0.001 occurred, too. All these features show that the proposed UWB MIMO antenna can meet the requirement of MIMO/diversity of communication applications well.