DYNAMICS CHARACTERIZATION IN RF MEMS VARIABLE CAPACITORS
D. GIRBAU, A. LÁZARO, L. PRADELL

Abstract. This paper presents the characterization of dynamics – actuation and release times, resonance frequency and damping – in two MEMS capacitors, using a system based on RF measurement techniques and instrumentation typically available in RF/microwave laboratories. The measure is obtained from the mechanical information contained in the amplitude of a RF signal proportional to the reflection coefficient of the capacitor. This high-frequency carrier is down-converted and detected, extracting the mechanical information from its envelope. The system is designed to measure both, 1-port MEMS capacitors (bias and capacity-testing in the same port) and 2-port extended tuning-range capacitors (bias and capacity-testing in different ports). Another important feature is the possibility of characterizing the dynamics of MEMS devices designed to work at very different operating frequencies in the RF/microwave range because the system is using downconversion and detection at IF.