High order mode distortion characterization of the open stateof capacitive RF MEMS switches

We present the first analysis for the generated distortion of higher order modes of capacitive RF MEMS switches in the open state. Distortion or IIP3 numbers are normally set independently of the tone spacing separation. However, MEMS switches present a more complicated structure that needs to be analyzed and reported for today's complex mobile communications. It is well-known how IIP3 numbers improve by +20dB/dec on MEMS switches beyond the resonance frequency. However, higher order modes can derate the overall performance at certain frequencies. For this reason, we have measured and characterized the distortion generated by higher order modes in the open state. Laser Doppler Vibrometer and AC measurements were made for this purpose.