Electromagnetic levitation of micro-scale actuators using microwave cavity resonators

The difficulties of achieving electromagnetic levitation of a small conducting disc, by employing the electric field distribution within the capacitive element of a high frequency resonant system, are discussed. It is shown that as the frequency of the system is raised in order to miniaturise it, the attractive electric levitation force is increasingly counteracted by an oppositely directed Lorentz force. This latter force has to be isolated if effective levitation is to be procured. In `standing-wave´ type microwave resonators, the separation of the electric field force and the Lorentz force calls for careful cavity selection and the judicious use of field-selective leakage apertures