Characterization of dynamics in on-wafer RF MEMS variable - capacitors using RF measurement techniques

In this paper we propose a new system to measure the dynamics of on-wafer RF MEMS variable capacitors -rise and fall times, resonance frequency and damping-, which is based on RF measurement techniques and instrumentation typically available in RFImicrowave laboratories. The amplitude of a RF carrier is modulated through the mechanical movement of the MEMS device. This high-frequency carrier is down-converted and detected, extracting the mechanical information from its envelope. This 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 capacitytesting 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 RFImicrowave range because the system is using downconversion and detection at IF. Two MEMS variable capacitors with different actuation principles -electrostatic and electrothermal- are characterized in terms of dynamics using the proposed system