High Q 3-bit linear digital MEMS capacitors

This paper presents the design and the performances of higb Q MEMS switched capacitor banks. Each device owned three switchable bits, has been optimized to achieve a constant capacitance step variation between their height states. The implementation of two kinds of MEMS switch (capacitive and DC contact) has been studied and experimental results demonstrate than very good performances can also be achieved with DC contact micro-relays as well as capacitive switches. These fabricated devices present measured Q values at least better than 150 with a ratio better than 1:2, making them suitable for low loss tunable apptications.