Despite the demonstrated performance advantages of RF MEMS switches, the technology to manufacture reliable, environmentally robust devices is still maturing. The dominant reliability issue with capacitive RF MEMS switches is charging of the switch dielectric. Switching voltages across a thin dielectric layer causes electrical charges to tunnel into the dielectric and become trapped within the insulator. As yet, the underlying physics of the charge tunneling and trapping is not well understood. Most of the present knowledge of this phenomenon has come from empirical measurement of the switches.
One novel method of circumventing the charging phenomena is by trading off switch performance for lifetime. Proximity switches, being developed by MEMtronics, enable low loss, effective operation at microwave and millimeter wavelengths without the detrimental effects of charging on switch lifetime. These switches have the potential for operating for > 100 billion cycles and handling hot switching at multi-watt power levels. At microwave and millimeter-wave frequencies, the reduced capacitance ratio of these switches (Con/Coff ~20-40) is still sufficient for constructing high-performance phase shifters and tunable filters.
Ver blogg: http://lennyramirez-crf.blogspot.com/