A research team from Binghamton University, State University of New York has created a way to build cellphones and power lines with increased durability. This is all thanks to a new type of microelectromechanical system (MEMS) switch that delivers robustness via electrostatic levitation.
“All cellphones use MEMS switches for wireless communication, but traditionally there are just two electrodes,” says Sherry Towfighian, Binghamton University assistant professor of mechanical engineering. “Those switches open and close numerous times during just one hour, but their current lifespan is limited by the two-electrode system.”
After two electrodes come into contact several times, damage starts to occur on the bottom electrode, according to Binghamton University. This damage means the MEMS switch either has to be replaced or discarded entirely.
Some researchers have tried to solve this issue by reducing the electrode contact area during collisions. According to Towfighian, however, this only delays the inevitable.
To steer clear of damage altogether, the team developed “a MEMS switch with three electrodes on the bottom and one electrode parallel to the others. The two bottom electrodes on the right and left side are charged while the middle and top electrodes are grounded,” according to Binghamton University.
“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,” says Towfighian.
Electrostatic levitation is the force mentioned above, which is not achieved in a two-electrode setup. By providing electrostatic levitation, damage is avoided while also enabling a dependable bi-directional switch.
“For cellphones, this design means longer life and fewer component replacements,” explains Towfighian. “For power lines, this type of MEMS switch would be useful when voltage goes beyond a limit and we want to open the switch. The design allows us to have more reliable switches to monitor unusual spikes in voltage, like those caused by an earthquake that can cause danger to public safety.”
Along with Towfighian, graduate student Mark Pallay was also part of the research team.
To learn more, you can read the study, “A reliable MEMS switch using electrostatic levitation,” published in Applied Physics Letters.