Design, fabrication and characterization of a bistable electromagnetic microrelay with large displacement

This paper reports the design, fabrication and characterization of a bistable electromagnetic microrelay based on non-silicon surface micromachining technology. It mainly consists of an integrated microcoil at bottom with a spacer, and a suspension spring with a permanent magnet on top. Bistable mechanism is realized by the adoption of the SmCo permanent magnet to hold the microrelay at latching position without current. Switching between two stable states is completed by the variation of current direction in the microcoil. The corresponding power consumption is 25 mJ. The fabrication processes of related components are presented. The test result shows that the bistable electromagnetic microrelay can work with low operation voltage pulse of 5 V. The output displacement is about 380 μm while the response time is about 4.96 ms. Besides, the test insertion loss is −0.02 dB and the isolation is −39.91 dB at 30 MHz.

► Large displacement is about 380 μm.
► Single-layer spiral coil is integrated with the magnetic york.
► Device can be kept at ON/OFF by permanent magnet without power consumption.