Fig. 3
From: Rapid global antenna design by simplex regressors and multi-resolution simulations

Relationship between the entire antenna characteristics and its geometry parameters versus analogous relationship for antenna operating parameters: (a) |S11| of a dual-band antenna form Fig. 2(b) at several trial points; (b) resonant frequencies f1 and f2 versus two (out of six) geometry parameters of the same antenna (random designs). The dependencies shown in panel (b) are clearly more linear than those presented in panel (a).