MEMS Based 3-D Micro Coaxial Transmission Lines

Micro coaxial transmission lines are advantageous over planar counterparts such as microstrip and coplanar waveguides due to their shielded nature for use at mm-wave frequencies. This paper proposes micro coaxial transmission lines implemented on CMOS grade silicon wafers, suitable for integration with conventional MMIC circuitry. Lines of varying characteristic impedances were designed, fabricated and analyzed in the 1 to 40 GHz range. Normalized best case return loss values are in the range of 15 dB and an insertion loss of 4 dB/cm at 30 GHz