Intermodulation distortion in MEMS capacitive switches under high RF power

Intermodulation distortion in MEMS capacitive switches was analyzed both theoretically and experimentally as a function of tone spacing and RF power. The theory and experiment consistently showed that, under high RF power, additional distortion was caused by self-heating of the switch membrane by the RF power, which decreased the membrane spring constant significantly. The results implied that, well before the input RF power triggers self-actuation, the distortion might increase rapidly to an unacceptable level, so that the power-handling capacity of MEMS capacitive switches would be limited by intermodulation distortion instead of self-actuation.