MEMS capacitive series switches: optimal test vehicles for the RF self-biasing phenomenon

This paper demonstrates the use of the cantilever series capacitive RF-MEMS switches to study qualitatively the RF self-biasing. These devices are less prone to RF Joule heating than the commonly used bridge shunt switches and exhibit the same self-actuation phenomena but at lower power levels and at lower frequencies. Therefore, series switches provide a much better test/study vehicle for this complex problem. Some new findings are the existence of the non-zero pull-out power and its dependence on the frequency, the increase or decrease of pull-in power with the frequency depending on the device characteristic, the closure of the instability window for the air gap height and the consequent full tuning range. Our model was validated with original measurements focusing on the frequency dependence of the RF self-actuation characteristics. This approach allows using a single structure to realize a qualitative verification of various phenomena predicted by our model.