In one embodiment of the invention, a MEMS structure includes a first electrode,
a second electrode, and a mobile element. The first electrode is coupled to a first
voltage source. The second electrode is coupled to a second voltage source. The
mobile element includes a third electrode coupled to a third voltage source. A
steady voltage difference between the first electrode and the third electrode is
used to tune the natural frequency of the structure to a scanning frequency of
an application. An oscillating voltage difference between the second electrode
and the third electrode at the scanning frequency of the application is used to
oscillate the mobile element. In one embodiment, the mobile unit is a mirror.