Figure 4

White noise loading: geometry and frequency characterisation of the resonators for the linear and optimised configurations. On top: geometry of (a) linear grading, (b) GA grading and (c) RL grading. On bottom: comparison between the first (equivalent) bending frequency of the resonator pairs, depicted by red diamonds, and the frequency spectrum of a possible random load for (d) linear grading, (e) GA grading and (f) RL grading.