One-Chip Integration of RF MEMS Switched Capacitor and Power Amplifier Using CMOS-Compatible Post Fabrication Process

This study presents a single-chip integrated reconfigurable 180-nm complementary metal-oxide-semiconductor (CMOS) power amplifier (PA) with a radio frequency micro-electro-mechanical system (RF MEMS) switched capacitor, which is highly useful for advanced wireless mobile communication systems. The proposed reconfigurable PA prototype was designed to support the 0.9, 1.8, 2.4, and 5.0 GHz quad-bands by varying the capacitance values of the RF MEMS switched capacitor at the output matching network. The RF MEMS switched capacitor was post-fabricated on the same silicon substrate with which the PA circuit was integrated using 180-nm CMOS fabrication technology. The entire fabrication step was performed based on a CMOS-compatible low-temperature post process to avoid the performance degradation of the CMOS PA circuit. The fabricated RF MEMS switched capacitor exhibited capacitances of approximately 1.0 and 3.9 pF at a frequency of 0.9 GHz in its OFF and ON states, respectively. The measured output powers of the integrated quad-band PA were 27.13, 26.63, 26.29, and 23.43 dBm at the frequencies of 0.9, 1.8, 2.4, and 5.0 GHz with the continuous-wave signal, respectively.