RF MEMS Characterization

The characterization of RF MEMS requires special measurement setups for the provision and detection of RF signals in addition to conventional measurement technology. For accurate measurement of components with a high Q-factor, such as MEMS varactors, interference effects (parasitics) must be excluded. This can be realized by direct injection of the signal at the DUT using coaxial RF probes with suitable pitch (75-1250 µm) as well as comparison measurements (calibrations) against known standards. Non-standard configurations are calibrated using the so-called "imperfectly known on-wafer standard", which is typically produced in conjunction with the DUT itself. RF MEMS operation requires controlled application of DC bias voltages. For this purpose, a software-controlled 4-channel DC high-voltage source is used. All measurements can be performed at wafer, chip or circuit level. A special RF probe station allows RF characterization of 4-port devices up to 50 GHz and 2-port devices up to 110 GHz. By combining with additional measurement technology, a combined analysis of RF performance and mechanical characteristics is also feasible.