Casals, J.; Llamas, M.; Girbau, D.; Pradell, L.; Lázaro, A.; Giacomozzi, F.; Colpo, S. Journal of microelectromechanical systems Vol. 23, num. 6, p. 1428-1439 DOI: 10.1109/JMEMS.2014.2314752 Date of publication: 2014-12-01 Journal article
In this paper, the dynamic behavior of electrostatically actuated radio frequency-microelectromechanical system (RF-MEMS) switches is analyzed using energy considerations. An analytical model for bridge-type RF-MEMS switches is proposed and the time evolution of the system total energy is calculated numerically. Switch actuation, release times, and damped release response are derived from energy analysis with focus on the effect of increasing the actuation voltage on the RF-MEMS dynamic behavior. The dynamic and RF characteristics of different RF-MEMS ohmic-contact switches have been measured using an experimental set-up based on microwave instrumentation. The measured results show a good agreement with simulations, thus validating the proposed analytical model. It is shown (theoretically and experimentally) that the damped release response increases the effective time to reach the RF/microwave OFF-state switch isolation (up to three natural periods of the mechanical system).
Llamas, M.A.; Ribó, M.; Girbau, D.; Pradell, L.; Lázaro, A.; Giacomozzi, F.; Margesin, B. International Conference on RF MEMS and RF Microsystems p. 1-4 Presentation's date: 2010-06-28 Presentation of work at congresses
A phase switch based on switching between two twoport
passive networks with a phase difference of 180º is reported.
Two RF MEMS single-pole-double-throw structures are used to
select the phase path. The fabrication is made on both highresistivity
silicon and quartz substrates using the eight-mask
FBK-irst surface micromachining process. The measured phase
shift is 180º±5º in the frequency range 14−20 GHz on quartz
wafers and in the range 8−20 Ghz on silicon wafers.
Pradell, L.; Girbau, D.; Pérez, A.; Lázaro, A.; Martínez, E.; Villarino, R. International journal of microwave and wireless technologies Vol. 2, num. 3-4, p. 245-253 DOI: 10.1017/S175907871000036X Date of publication: 2010 Journal article
This paper proposes the design of tunable dual-band
filters for multi-band multi-standard systems. The main
objective is to provide frequency tunability in the second band
while maintaining the first band fixed. To this end, the
capacitive-loaded stepped-impedance resonator is used. The
work is divided into two main parts. In the first part, a deep
analysis of the capacitive-loaded stepped-impedance resonator
structure is done, which provides analytical closed-form design
equations which eases their design in front of the several
approaches available in the literature up to now. The analysis is
also particularized for the case of the capacitive-loaded uniform
resonator. In the second part, resonators are integrated in two
dual-band tunable filters.
Girbau, D.; Lázaro, A.; Pérez, A.; Martínez, E.; Pradell, L.; Villarino, R. Simposium Nacional de la Unión Científica Internacional de Radio Presentation's date: 2009-09-17 Presentation of work at congresses