Design and analysis of a novel low actuation voltage capacitive RF MEMS switches

The novel design of capacitive RF MEMS switches using torsion spring is presented and analyzed in this paper. The RF MEMS switches not only have ordinary folded suspending beams, but also add torsion springs. The simulation results show that compared with ordinary bending deflection, the torsion deflection is sensibly influenced by the ratio of the arm width (b) and the arm thickness (t), so the actuation voltage (V_T) of the RF MEMS capacitive switches which have both the ordinary bending deflection and added torsion deflection will be obviously depressed. At same time, the theory analysis shows that the lower VT can be obtained with longer torsion arm length (L_D), longer driven arm length (LD).By optimizing the structure design of RF MEMS switches, when L_T, L_D, b and t are 180 um, 120 um, 5 um and 1 um, respectively, the area actuation electrodes is 120times120 um², the actuation voltages of RF MEMS switches is 1.5 V by computer simulating.