A Passive Wireless Switching Array Based on MEMS Switches

Passive wireless actuators have advantages similar to passive wireless sensors, which is also suitable for use in human body or sealed spaces that require wireless operation or control. This paper proposes a passive wireless switching array based on MEMS switches. By inductive coupling, AC signals are used as power as well as control signals at the same time. The switching system includes four switching branches, each of which is composed of a receiving inductor, an AC-DC convert circuit, a MEMS switch, and a load. The detail designs of the circuit part and the MEMS switch are provided, respectively. The MEMS switches are driven by electrostatic combs and are fabricated based on the SOI process. The average measured actuation voltage of the fabricated MEMS switches is 20.4 V. The error between the average measured value and the design value is within 5%. The AC control signals are set to 7.8 MHz, 6 MHz, 4 MHz and 1.8 MHz corresponding to the resonant frequencies of the four switching branches, and their peak to peak voltages are all set to 8V. Experiments verify that each AC control signal can and only can turn on its corresponding switching branch.