Tesis doctoral de Juan Luis Lopez Mendez
Mems devices demonstrated a wide range of sensing and actuation applications. These mechanical elements present nowadays extension to the rf world as key elements for highly reconfigurable systems, frequency references and signal processors. this thesis focuses on some of the applications of mems devices in the rf domain: frequency references for oscillators, filters and mixers. The resonators presented in this thesis are completely fabricated in commercial cmos technologies to take profit of monolithic mems and complementary circuitry integration and low cost fabrication inherent of these technologies. several kinds of mems resonators (clamped-clamped beams, free-free beams and double ended tuning forks) were designed and fabricated to evaluate their performance according to different properties. Two different cmos technologies, from two different foundries and also different technological node (0.35um and 0.18um) were successfully used to validate the monolithic fabrication approach on future cmos technologies. The resonance frequencies of these resonators are located on the hf and vhf range. All these devices, based on flexural beams, show superior q than integrated lc tanks and are also tunable. Moreover, their size is significatively lower than the one of the aforementioned lc tanks. The cmos-mems resonators reported in this thesis show a qxf value in the range between 1ghz and 10ghz in air and these values are further improved in vacuum up to 100ghz, higher than any other reported resonator based on cmos technology. filtering and mixing applications were also studied. The goal in these applications was to define a flat band-pass combining different resonators. A prototype of parallel filter was measured using two cc-beams and a monolithic cmos differential amplifier. The filter shows a flat bandpass up to 200khz in air at a center frequency of 21.66mhz. Filtering with a single resonator was also demostrated with a detf. A mixer based on a 22mhz cc-beam resonator was able to up and downconvert a signal from/to 1ghz. monolithic oscillators with mems elements as frequency references have shown oscillation with a reduced applied dc voltage (<5v) thanks to the reduction of the gap. The detf based oscillator shows good phase noise performance of -87dbc/hz@10khz and -98.7dbc/hz@100khz better than previously reported monolithic oscillators whereas operating at a lower dc voltage.
Datos académicos de la tesis doctoral «Application of cmos-mems integrated resonators to rf communications systems«
- Título de la tesis: Application of cmos-mems integrated resonators to rf communications systems
- Autor: Juan Luis Lopez Mendez
- Universidad: Autónoma de barcelona
- Fecha de lectura de la tesis: 21/09/2009
Dirección y tribunal
- Director de la tesis
- Nuria Barniol Beumala
- Tribunal
- Presidente del tribunal: joan Bausells roige
- ikka Tittonen (vocal)
- (vocal)
- (vocal)