In this paper, a compact 4-port band-notched multi-input-multi-output (MIMO) antenna with asymmetric coplanar strip (ACS) feed is presented for ultra-wide band (UWB) applications. The MIMO antenna is comprised of four semi-elliptical radiators with ACS feed for UWB applications and it is printed on inexpensive FR4 substrate of size 48 × 52 mm2 with ɛr = 4.4 and 1.6 mm height. The impedance characteristics of the suggested MIMO antenna ranges from 2.7 to 11 GHz with a band-notched behavior from 3 to 4 GHz to reduce the interception with WiMAX applications, and the isolation level over the achieved band is more than 20 dB between any two adjacent elements. Moreover, the radiation pattern of the proposed UWB antenna is almost omnidirectional with an average realized gain of 3.5 dBi over the entire achieved frequency band. The proposed ACS-fed antenna is confirmed by fabricating and measuring it's impedance and radiation characteristics. Finally, good consistency between simulation and measured outcomes is obtained confirming the validity of the MIMO antenna for real-life UWB wireless systems.
