Multiple-input multiple-output antenna for sub-sixGHz 5G applications using coupled folded antenna with defective ground surface

Abstract

A 6-element MIMO antenna system is introduced in this paper for N77, N78, and N79 (5G) communication bands. The proposed antenna element is composed of a four-section coupled line folded antenna. The performance of this antenna element is improved by using a partial ground plane combined with the DGS between the different elements of the MIMO antenna. The separated single antenna in this case has a reflection coefficient less than −10 dB over the frequency band from 3GHz to 5GHz. For the complete MIMO configuration, the reflection coefficient is less than −7dB over the same frequency band for all the antenna elements. On the other hand, the isolation between antenna elements in the MIMO configuration is greater than 15 dB. The values of the MIMO parameters are calculated. These parameters include the Envelope Correlation Coefficient between the different elements (ECC), Diversity gain (DG), Total Active Reflection Coefficient (TARC), Channel Capacity Loss (CCL), and Mean Effective Gain (MEG). Good results are obtained for the MIMO parameters where ECC < 0.006, DG = 10, TARC < −7, CLL < 0.6, and −3 < MEG < −8. These performance parameters of the proposed MIMO system indicate that this antenna is suitable for 5G applications. The effect of the human hand on the S-parameter is also investigated. The proposed antenna is fabricated and measured to verify the simulation results.