Efficient electromagnetic analysis of spiral inductor patterned ground shields

Patterned ground shields are widely used to increase the Q of spiral inductors on silicon. As RFIC (radio frequency integrated circuit) technology pushes toward deeper submicron nodes, the geometries of ground shields can become exceedingly complicated. This poses a huge challenge for numerical EM (electromagnetic) simulators. This paper explores several ground shield geometries and illustrates a new anisotropic conducting sheet model for efficient EM analysis of even the most complicated ground shield geometries by substitution of a continuous, but anisotropic conducting sheet. The technique is validated by comparison of EM analysis results using this new model to EM analysis results of actual ground shield geometries. We also explore visualization of the current induced in the silicon substrate by the inductor and (if present) the ground shield.