Non uniform meander based low actuation voltage high capacitance ratio RF MEMS shunt capacitive switch

This paper deals with the investigation of high C_on C_off ratio capacitive shunt RF MEMS switch and reports a detailed comparison between uniform three meander beam with non-uniform single meander beam RF MEMS switch. RF MEMS Switches are designed for operation in the range 5 -40 GHz. Static Pull in analysis is performed with gold as a beam material. Simulation reveals that use of high K dielectric material can drastically improve the capacitance ratio of switch. For the same geometry, pull in voltage is 2.45 V for HfO₂, 2.7 V for Si₃N₄ and Capacitive Ratio of the switch with Si₃N₄ is 83.75 and Capacitive Ratio with HfO₂ is 223 at 2g₀ (air gap) and 0.8 μm thickness of beam. The Radio Frequency performance of RF MEMS switch is obtained by scattering parameters analysis (insertion loss, return loss and isolation loss) which are mainly dominated by down to up capacitance ratio and MEMS bridge geometries. RF analysis shows that insertion loss as low as -0.4 dB at 20 GHz and isolation as high as -60 dB at 20 GHz can be achieved. Investigation of uniform three meander design and non-uniform single meander design reveals that use of non-uniform design reduces the design complexity and saves substrate area while maintaining almost same device performance. S-parameter analysis is carried out to compare device performance for both structures. DC analysis and beam deflection analysis of the proposed switch is carried out using FEM Coventorware and RF analysis is plotted in MATLAB.