Design and implementation issues for ceramic substrate micro RF relay switches for re-configurable antennas

摘要

The increasing requirements for antenna apertures with multiple functions in terms of frequency diversity, beam steering and beam shaping have lead to the concept of re-configurable antennas. RF MEMS switch technology is promising to enable the development of such structures. Through electromagnetic analysis, this research demonstrates the feasibility of using RF MEMS switches to facilitate the phase shifting required for phased array beam steering. A particular problem associated with the practical implementation of RF MEMS switches, the substrate choice, was investigated. Ceramic substrates have appropriate loss tangent coefficients and dielectric constant, however, the thermal mismatch between silicon nitride and other materials used to construct the mechanical parts of the switch introduces thermal mismatch stress and process problems during fabrication. Micro RF relay switches on a ceramic substrate have been fabricated and their pull-in voltage characteristics were measured and compared to the theoretical results for the RF relays.