An Improvement Approach for Wide-Angle Impedance Matching Using ELC Metasurface Slabs for SIW Slot Array Antennas

Figure 3

(a) S-parameters of the ELC2 resonator: , , , , , and . (b) S-parameters of the ELC resonator: , , , , , and (the operating band in this work is located in the yellow zone, the electric field response shows insulation property in the purple zone, and its corresponding permittivity is negative).

(a)

(b)