The AR and VSWR BWs are improved by doubling the substrate thickness to h = 0.318 cm. For L1 = 3 cm, L2 = 2.83 cm and feed along the diagonal at (-0.16L1, -0.16L2), the input impedance and AR variations with frequency are given in Figure 8.13.
A larger ratio of L1 /L2 = 1.06 is taken in this case, because BW increases with an increase in the substrate thickness.
For the SMA connector (probe diameter d = 0.12 cm), the kink in the input impedance plot is formed in the inductive region of the Smith chart, which is because of the larger probe inductance due to the increased
substrate thickness.