Fig. 3From: Fast design of multiband fractal antennas through a system-by-design approach for NB-IoT applicationsPRE block (SVR training). Plot of \(\widehat {f}_{n}\left (\mathbf {g}^{(t)}\right), n=1,..,N, t=1,...,T\) of the T=3721 OA-defined training samples (n=1→ blue cross; n=2→ green cross)Back to article page