Effect of a Local Ground and Probe Radiation on the Microwave Characterization of Integrated Inductors

Microwave characterization of an integrated inductor is often carried out with respect to a local ground reference. The measurement outcome, however, does not necessarily reproduce the behavior of the device in an actual circuit where a ground reference does not exist. Furthermore, inductor measurements can be affected by the unequal currents on the inner and outer conductors of the coaxial lines internal to the RF probes. Such currents tend to radiate the microwave energy into the surroundings and manifest themselves as unexpected ripple and resonance features in measurement results. In this study, a measurement model is developed including both effects and is used to analyze experimental data obtained from integrated spiral inductors. A novel deembedding technique is then proposed and applied to eliminate the local ground and unequal coaxial current effects.