Finite element results showing three-dimensional snapshots of several natural modes that are associated with the corresponding natural frequencies fi. (a) f5 = 26.515 kHz, (b) f20 = 28.865 kHz, and (c) f80 = 43.313 kHz illustrate cantilevers vibrating at the first harmonic. (d) f105 = 163.210 kHz, (e) f120 = 178.536 kHz, and (f) f180 = 266.109 kHz depict the cantilevers vibrating at the second harmonic.