Novel designs of RF MEMS SP4T and SP6T switches with improved performance are reported. The design optimization carried out having significant impact on the RF characteristics of these switches. The device takes advantage of the CPW transmission line with small width and spacing configured for 50Ω with ohmic-contact SPST switch. The results show significant improvement in insertion loss and isolation without any significant changes in other electromechanical and RF parameters. A systematic comparison of different configurations of CPW designs and SPST switch is performed. The simulated insertion loss and isolation are better than -0.238 dB and - 53.002 dB respectively for SP4T switch and - 0.2956 dB and -57.217 dB respectively for SP6T switch, at 8 GHz. © 2010 IEEE.