Compact wideband two-element millimeter wave MIMO antenna with CMT based modified T-shaped decoupling structure for mobile applications with estimated link budget in urban scenario

Today, almost all wireless application systems and devices are switching to millimeter waves (mmWave) to cater to the demand for low latency with higher data rates. A two-element MIMO antenna is proposed to support enhanced data rate and to cover a wide range of applications at 5G new radio (NR 2) band. The structure has a compact profile of 0.78 lambda(0)x0.36 lambda(0) (lambda(0) is the first resonance wavelength at 18 GHz). The radiating elements of MIMO are symmetrically arranged, which helps in expanding as required. A characteristic mode theory (CMT) is applied to optimize the decoupling structure (DCS) for better performance of the MIMO antenna. Hence, a modified T-shaped DCS is proposed in the article. The initial simple DCS shows an isolation of 15 dB; however, the proposed DCS has improved to > 20 dB. The CMT also shows that the structure generates three modes where Mode 1, 2, and 4 are naturally resonant over the entire bandwidth. The antenna measured a bandwidth of 16.38 GHz, operating from 16.26 to 32.64 GHz with a maximum gain of 5.4 dBi. The average efficiency of the antenna is 90 %. It has achieved bidirectional and omnidirectional radiation in E- and H-plane. The measured diversity parameters resulted in ECC of < 0.22, DG > 9.6, CCL < 0.25b/s/Hz, TARC < -10 dB, and MEG of < -4.3 dB. The performance of the antenna is analyzed inside the mobile casing materials. The resulting change in reflection coefficient is negligible; however, a slight impact on isolation and little variation in radiation pattern are seen. This article also performs link budget analysis in urban conditions for mobile communication. The results show that the antenna reliably communicates 1 Gbps data over 100 m and has a maximum data rate of 10 Gbps under line-of-sight conditions. Therefore, the proposed structure suits 5G mobile applications.