THE INTERDIGITAL COPLANAR WAVE-GUIDE - A NEW LOW-IMPEDANCE MICROMACHINABLE PLANAR STRUCTURE

This letter describes a new type of coplanar waveguide (CPW) which me call interdigital coplanar waveguide (ICPW). ICPW has three advantages over CPW. First, ICPW can have a lower characteristic impedance for t he same minimum feature size and overall line width. Second, at low im pedances it can obtain reduced high-frequency resistive loss. Finally, thickening the conductor reduces the ohmic losses more rapidly in the ICPW than in the CPW. This letter presents an analysis comparing CPW and ICPW assuming a TEM mode of propagation. Calculations are pel form ed using finite-element analysis, and volume filament and surface ribb on methods.