pression specifies the DG of the planned MIMO antenna [18]: DG=10,1-1pl2 where pis the coefficient of complex cross-correlation, and 1pl2 2 ECC. Figures 11.7 and 11.8 show the ECC and DG graphs that were simulated and measured. The radi- ation patterns are used to generate the simulated ECC and DG results, while the parameters are used to generate the measured results. 5G Wireless Communication System in Healthcare Informatics ECC PORT-1 ECC PORT-2 ECC PORT-3 ECC PORT-4 Freq (GHz) FIGURE 11.7 ECC of all ports of the proposed antenna. As we can see from Figure 11.7, the ECC is less than 0.03 for the whole ISM band, except in the frequency band (3-4.4GHz), where the ECC is greater than 1 db. As indicated in Figure 11.8, the DG is larger than 9.75 dB. 11.4.3.2 Efficiency The high radiation efficiency of over 83% backs up the compact 4-Port MIMO antenna's almost constant performance. 11.4.3.3 Total Active Reflection Coefficient For a four-port MIMO system, i = 1, 2, 3, 4, j = 2, 3, 4, 1 in that order and N = 4. The following equation considers the TARC using the S-parameters: where the Gaussian random input feed phase is 0, and it varies from 0 to T. As seen in Figure 11.9, this parameter is less than - -10 dB over the whole frequency range. The slight disparity between the simulated and observed findings could be related to the effect of soldering the SMA connectors, as well as the tolerance levels for the antenna construction process period. MIMO Antennas for loT and ISM Band W1-5mm W1-3mm Frequency (Ghz) W1(5mm) W1(3mm) 10.00 Frequency (GHz) FIGURE 11.8 (a-d) DG of all ports of antenna. 5G Wireless Communication System in Healthcare Informatics W1 (3mm) W1 (5mm) Frequency (GHz) W1 (3mm) W1 (5mm) 10.00 Frequency (Ghz) FIGURE 11.8 (continued) MIMO Antennas for loT and ISM Band W1 (3mm) W1 (5mm) Frequency (GHz) W1 (3mm) W1 (5mm) Frequency (GHz) FIGURE 11.9 (a-d) TARC of all ports of the proposed antenna. 11.4.3.4 Voltage Standing Wave Ratio (VSWR) The voltage standing wave ratio, or VSWR, is the ratio of a lossless l