## 2 Design of the Six-Element MIMO Antenna Structure
The associated peak gain and bandwidth values are represented in Table 4 for a suitable comparison of the derived resonating frequency bands for different antenna designs. The radiation pattern of the antenna and intensity of the normalized electric field for the multi-port excitation conditions are derived, and the results are presented in Figures 7-11. Figure 7 shows the changes in electric field for the multi-port excitation conditions such as (P1, P2 = (0, 1)), (P1, P2 = (1, 0)), and (P1, P2 = (1, 1)) for Design 1 of the MIMO antenna structure. Similarly, the co- and cross-polarization of the structure is shown for these port excitation conditions in Figure 7b,d,f. For all-port excitation, we've additionally shown the radiation pattern in 3-D distribution, as shown in Figure 7g. We have also simulated antenna structure 2 for electric field intensity and radiation patterns. Figure 8 shows these results for the multi-port excitation conditions such as (P1,P2,P3 = (1,0,0)), (P1,P2,P3 = (1,1,0)), and (P1,P2,P3 = (1,1,1)) in the form of radiation beams. Figure 7: Electric field intensity and polar radiation pattern for the Design 1. Normalized electric field distribution for the different port excitation conditions such as (**a**) (P1 = 0, P2 = 1) (**c**) (P1 = 1, P2 = 0), and (**e**) (P1 = 1, P2 = 1). Co-polarization and cross-polarization 2D radiation pattern for the different port excitation conditions such as (**b**) (P1 = 0, P2 = 1), (**d**) (P1 = 1, P2 = 0), and (**f**) (P1 = 1, P2 = 1). (**g**) three-dimensional radiation pattern along with the electric field distribution for the (P1 = 1, P2 = 1) condition. Figure 8: Electric field intensity and polar radiation pattern for the Design 2. Normalized electric field distribution for the different port excitation conditions such as (**a**) (P1 = 1, P2 = 0, P3 = 0), (**c**) (P1 = 1, P2 = 1, P3 = 0), and (**e**) (P1 = 1, P2 = 1, P3 = 1). Co-polarization and cross-polarization 2D radiation pattern for the different port excitation conditions such as (**b**) (P1 = 1, P2 = 0, P3 = 0), (**d**) (P1 = 1, P2 = 1, P3 = 0), and (**f**) (P1 = 1, P2 = 1, P3 = 1). (**g**) three-dimensional radiation pattern along with the electric field distribution for the (P1 = 1, P2 = 1, P3 = 1) conditions. Figure 9: Electric field intensity and polar radiation pattern for the Design 3. Normalized electric field distribution for the different port excitation conditions such as **(a)** (P1 = 1, P2 = 1), **(c)** (P3 = 1, P6 = 1), and **(e)** (P1 = 1, P5 = 1, P6 = 1). Co-polarization and cross-polarization 2D radiation pattern for the different port excitation conditions such as **(b)** (P1 = 1, P2 = 1), **(d)** (P3 = 1, P6 = 1), and **(f)** (P1 = 1, P5 = 1, P6 = 1). **(g)** three-dimensional radiation pattern along with the electric field distribution for the all-port excitation conditions. **(h)** Co polarization and cross polarization 2D radiation pattern for all port excitation conditions. Figure 10: Electric field intensity and polar radiation pattern for the Design 4. Normalized electric field distribution for the different port excitation conditions such as **(a)** (P1 = 1, P2 = 1), **(c)** (P3 = 1, P6 = 1), and **(e)** (P1 = 1, P5 = 1, P6 = 1). Co-polarization and cross-polarization 2D radiation pattern for the different port excitation conditions such as **(b)** (P1 = 1, P2 = 1), **(d)** (P3 = 1, P6 = 1), and **(f)** (P1 = 1, P5 = 1, P6 = 1). **(g)** three-dimensional radiation pattern along with the electric field distribution for the all-port excitation conditions. **(h)** Co polarization and cross polarization 2D radiation pattern for all port excitation conditions. Figure 11: Electric field intensity and polar radiation pattern for the Design 5. Normalized electric field distribution for the different port excitation conditions such as **(a)** (P1 = 1, P2 = 1), **(c)** (P3 = 1, P6 = 1), and **(e)** (P1 = 1, P5 = 1, P6 = 1).