Willem Frederik Adrianus Besling

Small, low-ohmic RF MEMS switches with thin-film package

We report on small, low-ohmic RF MEMS switches with a circular membrane actuator design. A low temperature process is used to manufacture both the MEMS switch as well as its hermetic, thin-film package resulting in a very small footprint device. The hermetic seal of the package significantly increases the switch lifetime and reliability. The switches demonstrate good RF performance and high switching speeds. A comparison with other MEMS switches reveals that these MEMS switches possess a low on-resistance while occupying only a very small area on the wafer.

MEMS oscillating squeeze-film pressure sensor with optoelectronic feedback

This work reports on an oscillating pressure sensor that converts pressure into frequency using the squeeze-film effect. A new aspect is the laser Doppler vibrometer (LDV) in the optoelectronic feedback loop that is used to bring the sensor element into sustained mechanical oscillation. A phase shifter and automatic gain control circuit stabilize the oscillation. The frequency stability of the pressure sensor is investigated by measuring its Allan deviation and is compared to the performance of a quartz oscillating pressure sensor. Finally, the pressure resolution of this oscillating sensor is compared to conventional pressure sensors.