In this paper, improved RF MEMS SP4T and SP6T switches using a new design and layout topology, having significant impact on the RF characteristics of the device are presented. The device takes advantage of the CPW transmission line with small width and spacing configured for 50Ω line impedance in ohmiccontact 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 obtained for SP4T and - 0.2956 dB and -57.217 dB for SP6T switch at 8 GHz respectively. © 2009 IEEE.