Design and Analysis of a 4-Port MIMO Microstrip Patch Antenna for 5G Mid Band Applications

Abstract

This article proposes a 4-port MIMO antenna for 5G mid-band application resonating from 4.5–5.1 GHz which comes under n79 band, an FR1 5G NR band used in smart phones. The first design involves a single-element microstrip patch antenna with a diamond shaped slots and partial ground structure of size 30 × 43 × 1.6 mm3. Using this single element antenna as reference, a 4 port MIMO antenna is presented which operates at 4.9 GHz resonance frequency with proper spacing, resulting in much improved isolation between the elements. The proposed 4 port MIMO antenna is designed and fabricated over a commercially available low-cost FR-4 substrate having a relative dielectric permittivity of 4.4 and thickness of 1.6 mm. The W ×L dimension of this MIMO antenna is 56×56 mm2. Simulation of the S-parameters and radiation pattern of all purposed designs is performed using the CST studio suite, and test results of the return loss are presented using the Keysight N9916A 14 GHz vector network analyzer. Antenna gain is 3.8 dB, and efficiency is 87% with a low (less than 0.1) envelope correlation coefficient (ECC) between any two radiating elements, paired with a positive diversity gain (DG), indicating that the proposed antenna is well designed. As a result, the proposed antenna is an excellent candidate for deployment in 5G networks.