(a) Magnitude of the S-parameters of the two-Yagi Uda antenna system depicted in Figure 8 and relative (b) forward and backward gain. In the insets, it is possible to appreciate the 3D radiation pattern of the first Yagi-Uda at 0.93 GHz and of the second one at 3.2 GHz, respectively. Please note that, as desired, the two antennas radiate in opposite direction and do not affect each other in terms of both electrical and radiative characteristics.