A 1.5–2.4 GHz tunable 4-pole filter using commercial high-reliability 5-bit RF MEMS capacitors

This paper presents a 1.5-2.4 GHz 4-pole tunable filter using the Cavendish Kinetics RF MEMS capacitors. The MEMS capacitors are fabricated and fully packaged using a 0.18 μm CMOS standard process with integrated high voltage drivers and SPI control logic and with reliability in the billions of cycles. The filter results in a power handling of at least 20 dBm, a second and third harmonic generation of <; -125 dBc at 20 dBm, and an OIP3 of 33-35 dBm. The measured ACPR (adjacent channel power ratio) for a 5-MHz Wideband CDMA signal is ~45-48 dBm at 20 dBm input power. The paper also discusses the requirements on RF MEMS capacitors in order to achieve high performance filters for wireless systems.