Abstract
A novel, compact 2 x 2 ultra wideband multiple input multiple output (MIMO) antenna system is presented. The antenna system is capable of ultra wideband operation covering the defined UWB region of 3.1 GHz to 10.6 GHz. whereas, the overall bandwidth of the designed antenna is from 2 GHz to 13 GHz. It is worth mentioning that this antenna system additionally covers all the IEEE 802.11 standards. Special attention has been paid to keep the size with in miniature regime. A comparison of physically measured and simulated results has been presented. In both the cases, the return losses remain below -10 dB with in the operational band. However, at frequencies of 5 GHz and 9 GHz, significantly lower loss values were observed, additionally a return loss of -25 dB at center frequency has been recorded. Over the transmission bandwidth a mutual coupling value below 20 dB has also been recorded. The far field pattern at center frequency remained very close to isotropic far fields and this was measured in E and H. In terms of maximum gain the measurement came up to 4.7 dB. Achievement of satisfactory results with regard to envelope correlation coefficient (ECC) and diversity gain, agreement between simulation and practical measurements is reported. In ultra wide band (UWB) response, the fractional bandwidth of antenna system was measured as 141.5%, which is also with in defined limits.