RF MEMS tunable band reject filter using metamaterials

Abstract

Tuneable band reject filter is a very critical component of electronic warfare. The design is of such a filter using MEMS technology presented on CPW transmission line on silicon substrate using Complementary Split Ring Resonators (CSRRs) and RF MEMS variable capacitor, enabling compatibility with planar IC technology. The CSRRs are etched on both the signal line and ground planes of the CPW. Tunability of the band reject filter is achieved by putting the MEMS bridge in either up or down state. Through electrostatic actuation of the RF-MEMS switched capacitor, the electrical characteristics of the filter is modified, so that its resonance frequency can be tuned. The rejection of stop bands are around -20.19dB for down state around the centre frequency 35.32GHz and -18.29dB for up state around the centre frequency 38.80GHz.