Multilevel finite ground coplanar line transitions for high-density packaging using silicon micromachining

A 3D photolithographic technique is exploited to produce finite ground coplanar (FGC) transmission lines that transition into and out of silicon micromachined cavities. Each transition was found to introduce an average loss of less than 0.08 dB across the 2-40 GHz range for a cavity depth of 110 /spl mu/m. The demonstration of this technology is a significant step toward fully realizing the circuit packaging capabilities of micromachined silicon and offers the possibility of novel, broadband vertical transitions.