Mathematical analysis and test of an electrostatically actuated micro-power relay

This paper reports a mathematical and experimental study on a micro-relay for power applications. The relay is microfabricated using UV-LIGA and electrostatically actuated. The relay was uniquely designed with all major components made of metals except two polymer strips which serve as both mechanical connectors and electrical insulators. The utilization of UV-LIGA fabrication technologies helps to achieve high aspect ratio metal structures in the relay, which helps to achieve high power capacity. Both the static and dynamic characteristics of the prototype relay have been studied. The performances of the prototype relay agreed very with those predicted using mathematical models. The prototype relay was found to be able to operate in a control voltage lower than 18 V and carry a current of 5 A. The prototype relay operated over 10⁶ cycles without any degradation. In addition, the response time of a relay was 3.2–3.5 ms in the “on” operation and 7.9–14.3 ms during the “off” operation.