Low Actuation Voltage RF MEMS Switch Using Varying Section Composite Fixed-Fixed Beam

Abstract

The present authors have earlier reported the employment of varying section fixed-fixed beam for achieving lower pull-in voltage with marginal fall in restoring force. Reducing Young’s modulus also reduces the pull-in voltage but with lesser degree of reduction in restoring force. Composite beams are ideal alternatives to achieve decreased Young’s modulus. Hence new varying section composite fixed-fixed beam type RF MEMS switch has been proposed. The main advantage of this RF MEMS switch is that lower pull-in voltages can be achieved with marginal fall in stiction immunity. Spring constant of the proposed switch has been obtained using simulation studies and it has been shown that the spring constant and therefore the pull-in voltage (Vpi) can be considerably reduced with the proposed switch. Simulation studies conducted on the proposed switch clearly demonstrate that the pull-in voltage can be reduced by 31.17% when compared to the varying section monolayer polysilicon fixed-fixed beam. Further this approach enables the designer to have more freedom to design lower pull-in voltage switches with improved stiction immunity.

An inherent nonlinear electrostatic actuator without any additional auxiliary to reduce pull-in voltage and extend travel range

“…A high operation voltage may cause many catastrophic failures, such as insulation breakdown and stiction failure due to dielectric charging and electrical discharge [8][9][10]. Decreasing the effective stiffness constant of the suspension spring is a feasible method to reduce driving voltage [11,12], but the decrease of the stiffness with marginal reduction in restoring force would lead to be more prone to adhesion failure. Therefore, how to reduce voltage is also a noteworthy issue for an electrostatic actuator.…”