igure 11.5. 11.4.2.2 Gain That portion of the radiation intensity in a given direction corresponding to a cer- tain polarisation divided by different radiation intensity which can be obtained if the antenna's power was radiated in an isotropic manner. The total sum of the partial gains for any two orthogonal polarizations is the total gain of an antenna in a given direction. Losses due to impedance and polarisation mismatches are not included in the gain. If an antenna has no dissipative loss, its gain is equal to directivity in any direction. The direction of the peak radiation intensity is assumed if the direction is not provided. The simulated and the measured gain plot of the proposed MIMO antenna is shown in Figure 11.6. 11.4.3 PERFORMANCE PROVIDING PARAMETERS OF MIMO ANTENNA In the following subsection, the performance of the proposed compact 4-Port MIMO antenna construction including the terms DG, ECC, TARC, and efficiency is discussed in depth. Max: 5.4 Gain Plot 1 dB(GainTotal) Theta (deg) dB(GeinTetal) Min: -20.6 FIGURE 11.5 3-Dimensional polar plot of the proposed antenna design. MIMO Antennas for loT and ISM Band Gain (dB) Freq (GHz) FIGURE 11.6 Gain plot of the proposed antenna. 11.4.3.1 Envelope Correlation Coefficient and Diversity Gain The ECC between the ith and jth radiation elements of an N port MIMO antenna system using far-field patterns is given by Equation (11.1). (Eq. 11.1) where XPR represents the cross-polarization power ratio of the propagation surroundings. In the above formula, E (I) E*O (I) and E (S) E* (I) are the power patterns of 0 and Q polarizations, correspondingly. P (S) and P (S) indicate the angular density functions of the 0 and Q polarizations, correspondingly. Eo (I) and Eoj (I) are the electric field patterns of the ith and jth antenna elements in the 0 polar- ization, in that order. Eqi (S) and Eqj(52) are the electric field patterns of the ith and jth antenna elements in the Q polarization, individually. For uniform multipath environ- ment, XPR = 1 and The following ex