Isolation Improvement of an Overlapped Two-element MIMO Antenna

Abstract

Abstract An overlapped two-element antenna structure with excellent compactness is proposed. Extraordinarily strong mutual coupling is effectively mitigated by a decoupling network with simple coupled microstrip lines connected to the antennas in shunt. Simulation example and results are demonstrated. The isolation improvement is better than 8 dB (from about 2 dB to over 10 dB) in most of the Wi-Fi 2.4 GHz band. Four lumped components networks are utilized to maintain the good impedance matching before and after decoupling, and the return loss is higher than 7 dB over the band of interest. Remarkable decrease in envelope correlation coefficient (ECC) in most of the working band is achieved. All these performances prove the presented antenna structure and decoupling scheme a promising option for those mobile terminals and wireless communication devices which have high data rate and compact volumes.