Real-time monitoring of contact behavior of RF MEMS switches with a very low power CMOS capacitive sensor interface

This paper presents the first ultra-low power, fully electronic methodology for real-time monitoring of the dynamic behavior of RF MEMS switches. The measurement is based on a capacitive readout circuit composed of 67 transistors with a 105 µm x 105 µm footprint consuming as little as 60 µW. This is achieved by accurately sensing the capacitance change around the contact region at sampling rates from 10 kHz to 5 MHz. Experimental and simulation results show that timing of not only the first contact event but also all subsequent contact bounces can be accurately measured with this technique without interfering with the switch performance. This demonstrates the potential of extending this technique to real-time on-chip dynamic monitoring of packaged RF MEMS switches through their entire lifetime and after their integration in the final system.