ORIGIN AND EFFECTS OF INTERMODULATION IN RF MEMS CAPACITORS
D. GIRBAU, N. OTEGI, A. LÁZARO, L. PRADELL

Abstract. This work presents a study of intermodulation distortion in RF MEMS capacitors. The generation of 3^rd and 5^th order distortion and its origin in the displacement of the mobile membrane, are demonstrated. A numerical non-linear model for simulating intermodulation is presented and validated by means of measurements for the general 2-tone case. It is shown that, along with intermodulation, the two RF tones at a MEMS capacitor also generate a time-varying capacity. Generation of intermodulation in MEMS driven by digitally-modulated communication signals is also demonstrated, and its main effects are characterized. A measurement set-up to measure IMD for 2-tone test as well as for digital modulations is proposed.