Novel low-cost on-chip CPW slow-wave structure for compact RF components and mm-wave applications

In this paper, an ideal slow wave coplanar waveguide (CPW) structures with low losses, moderate impedance and CMOS fabrication technology have been developed. The slow wave CPW transmission line structures were achieved through IBM 0.13 mum technology with multi-layer metals. The CPW were implemented with narrower signal line or wider separation between signal and ground plane to increase the inductance per unit length, while metal strips on another metal layers cross under/above the CPW lines, which are orthogonal to signal propagation direction. Losses reduction using via bars to increase the thickness of the signal metal layer, structures with metal strip options (above, under and both CPW) to increase the capacitance per unit length of the CPW and provide more flexibility for the proposed structure, effect of the metal strips pitch are also discussed. The slow wave structure discussed in this paper can shrink the side dimension of the mm-wave passive components by up to 35%.