Novel RF MEMS Switch Driver for Longer Switch Life and Failure Detection
Micro-Electromechanical System or MEMS are small electromechanical devices such as switches, cantilevers and mirrors with features from a few microns to a few millimeters in size. Following the commercial success of MEMS technology used in in-jet printer head, pressure sensor and more recently the microaccelerometer, RF MEMS switch is fast joining the "commercially lucrative" MEMS ranks due to its outstanding performance. However, these switches are still in their early generations and the following issues have to be addressed before they can enjoy a much wide market acceptance:
Interestingly, the main cause of the switch failure is not mechanical, as many MEMS switches have endured 100 billion cycles without noticeable mechanical failure. Instead, the failure is caused by the large electric field across the thin dielectric in between the switching membrane and the electrode on the substrate when actuation voltage is applied. Therefore, minimizing the actuation voltage is one of the key to enhance the switch reliability.
b. Temperature dependent actuation voltage.
RF MEMS switch may be required to operate in extreme varying temperature environment. Aircraft condition monitoring for example, requires the switch to operate from -60°C to +50°C. The threshold actuation voltage varies with temperature where higher voltage is required when the switch is operating at low temperature.
c. Failure detection
The failure of the MEMS switch is gradual, but with abrupt deterioration as it nears complete failure.
The project aims at developing a generic Microelectromechanical (MEMS) switch power driver to enhance the switch lifetime and provide a pre-failure warning mechanism. It is an extension of the previous project SUTS started with Universiti Kebangsaan Malaysia (UKM) in 2006. SUTS has successfully obtained fund totaling RM199,000.00 from MOSTI through the Ministry' s ScienceFund scheme for this project.