Compact ultrawideband MIMO slot antenna with high isolation

An ultrawideband multiple-input-multiple-output (MIMO) slot antenna with a small size and high isolation is introduced. Two multi-stepped microstrip lines are used to feed the MIMO antenna and the ground plane is designed in a defective structure for achieving good impedance matching in an ultrawide frequency range. A 3T-shaped strip is utilized to diminish the coupling between the two microstrip feed lines for isolation improvement over the operating band. Two open-end rectangular slots are attached in the ground plane of the MIMO antenna to generate anti-phase current for further enhancing the isolation. By using this novel method, a compact ultrawideband MIMO slot antenna is designed and measured. It obtains an ultrawide bandwidth of 162.0%, ranging from 0.63 to 6 GHz, and excellent isolation of beyond 20 dB. Additionally, our MIMO antenna achieves a very low envelope correlation coefficient (ECC) of below 0.005, indicating its good diversity performance. A compact MIMO slot antenna with ultrawide bandwidth of 162.0% and high isolation of beyond 20 dB is introduced. Two multi-stepped microstrip lines are used to feed the MIMO antenna and the ground plane is designed in defective structure for achieving good ultrawide bandwidth. A 3T-shaped strip is utilized to diminish the coupling between two ports. Two open-end rectangular slots are cut in the reflector plane to generate anti-phase current for further enhancing the isolation. image