Scientists introduce a new type of microelectromechanical system, commonly known as a MEMS switch, which can make cell phones and power lines more durable.
Assistant Professor Sherry Towfighian and graduate student Mark Pallay, from the Mechanical Engineering Department of Binghamton University, have developed a MEMS switch that uses electronic levitation to bring forth a more powerful system.
The new study was published in the journal Applied Physics Letters on Nov. 20, 2018. The research received funding from the National Science Foundation's Division of Electrical, Communications and Cyber Systems.
New MEMS Switch
According to Towfighian, cell phones, which use MEMS switches for wireless communication, typically have only two electrodes. The researchers explained that the collision of the two electrodes, after a number of times, causes damage to the surface of the bottom electrode, requiring replacement or discard of the MEMS switch.
Some attempted to prevent the damage by adding dimples or landing pads to the electrodes to narrow the contact area during the collision. However, Towfighian pointed out that it just extends the lifespan of the MEMS switch for some time and it will still break down.
In this regard, the researchers saw the need to come up with a new system that eschews the damage. Towfighian and colleague Pallay designed a MEMS Switch with three electrodes on the bottom and one electrode that is aligned with other electrodes.
The middle electrode of the three bottom electrodes and the one on top are grounded. The bottom electrodes on the right and left side are charged.
"This type of MEMS switch is normally closed, but the side electrodes provide a strong upward force that can overcome the forces between the two middle electrodes and open the switch," explained Towfighian.
The three-electrode system is able to produce this strong upward force referred to electrostatic levitation. This force curbs the damage on the device after consistent use and enables a dependable bi-directional switch.
The researchers found that this new type of MEMS switch extends the lifespan of cell phones and reduces the need for component replacements. As for the power lines, it means having more reliable switches to keep track of spikes in voltage that may pose danger to the public.