A novel printed 2×1 MIMO using circular monopole antenna with bandwidth more than ultra-wide band 1.6-16 GHz and reconfigurable single and dual band notch characteristics with integrated bluetooth band is presented. Reconfigurable notches at WiMAX and WLAN with return loss -5.7 dB and -3.5 dB respectively are designed to reduce interference from the narrow band wireless services which exist within the ultra-wide band. The mutual coupling coefficient between antenna elements of MIMO is less than -15 dB over the entire band. The proposed antenna has low envelope correlation coefficient and high diversity gain for mitigation to multipath fading. Thus, the designed antenna provides a good solution for spectrum sensing and spectrum allocation using reconfigurable characteristics for cognitive radios. The reconfiguration of notch bands is simulated using equivalent circuit for diode to show RF switching.