Scattering Parameters of Broadband (18 – 40 GHz) RF MEMS Switch in p-match Configuration

Abstract

This paper discussed about radio frequency design of coplanar-waveguide (CPW) based p-matched shunt switch for broad-band (18-40 GHz) application. The effects of variation in membrane width (50 – 80 µm) of the switch and high-impedance transmission line length (200 – 600 µm) between the switch structures on scattering parameters are studied. The variation in beam width has very little effect on return loss and insertion loss of the switch in the up-state. The reduction in high- impedance transmission line length yields marginally improved return loss and insertion loss. In the down-state configuration, the return loss showed negligible change with the variation in beam width and high-impedance transmission line lengths. The isolation is found to be improved with the increase in beam width and high-impedance transmission line length in whole frequency range. The optimized high- impedance transmission line length (400 µm) and beam width (50 µm) yields insertion loss< – 1 dB and isolation better than – 40 dB in 18-40 GHz frequency range.

Keywords

• Radio frequency MEMS
• Shunt switch
• Scattering parameters.