Quantifying Dynamic Impedance Matching Losses and Battery Life Degradation
Dynamic impedance matching losses double RF current draw and accelerate battery internal resistance growth, cutting endpoint service life by over fifty percent.
Mems Switches
Meaning
Electromechanical components fabricated on a silicon substrate use micro-scale moving parts to open or close an electrical contact. Designing with mems switches provides high-frequency systems with low insertion loss and high isolation compared to solid-state alternatives. These micro-devices are integrated directly into radio frequency front-end modules.
Actuation Mechanism
Electrostatic forces are typically used to pull a thin metal beam down to make contact with a signal pad. This mechanical action requires a specific actuation voltage, which can range from twenty to eighty volts. The mechanical movement of the beam dictates the switching speed, which is slower than that of semiconductor switches.
Electrostatic actuation keeps the continuous power consumption of the device extremely low.
Contact Reliability
Metallic contacts are subject to wear, material transfer, and stiction over millions of switching cycles. Overcoming stiction requires careful choices of contact materials and beam restoration forces. Hermetic packaging is necessary to protect the delicate microstructures from humidity and dust particles.
Protecting the contact surfaces from contamination extends the operational life of the switch.
RF Performance
Isolation is determined by the physical separation between the open contact and the signal lines. When open, the switch behaves as a very small capacitance, blocking high-frequency signals. When closed, the direct metal-to-metal connection presents a very low resistance to the signal flow.
This behavior enables high performance in antenna routing and filter tuning networks.