  We apply the equation-of-motion method to study the collective excitation
spectrum from a filled Landau level in rotating dipolar Fermi gases. The
predicted excitation spectrum of rotating dipolar Fermi gases can exhibit a
roton-minimum character. This roton character is tunable by varying the dipole
interaction strength and confining potential. An increase of the dipole
interaction strength makes the roton minimum becoming zero, and the system
becomes unstable. We also obtain a condition for the dynamical stability of
rotating dipolar Fermi gases.
