Performance analysis of RF MEMS capacitive switch with non uniform meandering technique

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This Paper reports on investigation of High Con Coff ratio Capacitive Shunt RF MEMS Switch and 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. 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 (insertion loss, Return loss and isolation) which are mainly dominated by down to up capacitance ratio and MEMS bridge geometries. RF analysis shows that insertion loss as low as ź0.4 dB at 20 GHz and isolation as high as 80 dB at 20 GHz can be achieved. Investigation of three uniform meander Design and non-uniform single meander design reveals that use of non-uniform design reduces the design complexity and saves substrate area still maintaining almost same device performance. S-parameter analysis is carried out to compare device performance for both structures. DC analysis of the proposed switch is carried out using Coventorware and RF analysis is performed in MATLAB.