Elevated-CPW for high-speed digital interconnects

An elevated coplanar waveguide is one in which the signal line is elevated. An elevated-CPW (ECPW) with low loss and low dispersion characteristics is proposed for high-speed digital circuits and its performance is predicted by theoretical analysis. The ECPW is simulated with FDTD and is fabricated as a 10 /spl mu/m elevated CPW using thick film micromachining technology and a polymide buffer layer. An ECPW has 10 dB lower insertion loss than the conventional CPW, and the effective permittivity is in the range of 1 to 3. Characteristic impedances and effective permittivity are given for various geometrical parameters.