Electromagnetic levitation of micro-scale actuators using microwave cavityresonators

The difficulties of achieving electromagnetic levitation of a small conduct ing disc, by employing the electric field distribution within the capacitiv e element of a high frequency resonant system, are discussed. It is shown t hat as the frequency of the system is raised in order to miniaturise it, th e attractive electric levitation force is increasingly counteracted by an o ppositely directed Lorentz force. This latter force has to be isolated if e ffective levitation is to be procured. In 'standing-wave' type microwave re sonators, 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.