Fig 1.
Single-port configuration (a) Oblique view, (b) Front view, (c) Back view, (d) S-parameters, (e) Impedance.
Table 1.
Dimensions of the single-port antenna.
Fig 2.
Evolution of single antenna configuration (a) Step A, (b) Step B, (c) Step C, (d) Step D, (e) Step E, (f) S11 for steps A to E.
Fig 3.
Surface current distribution at (a) 28.0 GHz; Parametric study for (b) R1, (c) g.
Table 2.
RLC values of the antenna at 28.0 GHz.
Fig 4.
(a) Equivalent circuit model of the antenna element, (b) S11 plot.
Fig 5.
Unit cell of the FSS (a) Port excitation, (b) Boundary conditions, (c) Dimensions, (d) S-parameters.
Fig 6.
FSS array (6 × 6) (a) Oblique view, (b) Parametric study, (c) Gap between single-port antenna and FSS array, (d) Oblique view of antenna and FSS array, (e) Gain comparison.
Fig 7.
Two-port MIMO antenna (a) Configuration (b) S-parameter results, (c) Surface current density at 28.0 GHz with single-port excitation, (d) Surface current density at 28.0 GHz with dual-port excitation.
Fig 8.
Four-port MIMO antenna (a) Configuration, (b) Reflection coefficients, (c) Transmission coefficients, (d) Surface current density at 28.0 GHz with single-port excitation, (e) Surface current density at 28.0 GHz with four-port excitation.
Fig 9.
Eight-port MIMO antenna (a) Side view, (b) Slant view with dimensions, (c) Fabricated prototype, (d) Fabricated prototype of 10 × 10 FSS array, (e) Slant view of antenna integrated with FSS, (f) FSS-based MIMO antenna connected to VNA for S-parameters measurement, (g) Simulated reflection coefficients of the FSS-based MIMO antenna, (h) Simulated transmission coefficients of the FSS-based MIMO antenna, (i) Measured reflection coefficients of the FSS-based MIMO antenna, (j) Measured transmission coefficients of the FSS-based MIMO antenna.
Fig 10.
Diversity performance analysis (a) Simulated ECC, (b) Measured ECC, (c) Simulated DG, (d) Measured DG, (e) Simulated TARC, (f) Measured TARC, (g) Simulated CCL, (h) Measured CCL, (i) Surface current density (SCD) with port 1 excitation, (j) SCD with ports 1 and 2 excitation, (k) SCD with ports 1, 2, and 3 excitation, (l) SCD with ports 1, 2, 3, and 4 excitation, (m) SCD with ports 1 to 5 excitation, (n) SCD with ports 1 to 6 excitation, (o) SCD with ports 1 to 7 excitation, (p) SCD with ports 1 to 8 excitation.
Table 3.
Surface current density for the eight-port MIMO antenna integrated with FSS.
Fig 11.
Far-field measurement (a) Antenna prototype inside the anechoic chamber, (b) Peak gain and Radiation efficiency, (c) 2-D radiation pattern at 28.0 GHz in elevation plane, (d) 2-D radiation pattern at 28.0 GHz in azimuth plane, (e) Surface current density for eight-port MIMO antenna without FSS, (f) Surface current density for eight-port MIMO antenna with FSS.
Table 4.
Electrical properties of tissue model at various frequencies [39,40].
Table 5.
SAR values of the eight-port MIMO antenna without and with FSS.
Table 6.
Comparison of the proposed work with existing antenna designs.