Quality factor and inductance in differential IC implementations

Monolithic inductors are widely used in microwave ICs and RFICs. Design considerations for inductors on low-resistivity substrates have been described. A /spl pi/-equivalent model, used to account for various loss mechanisms, can be helpful in understanding differences in the definition of L and Q for single-ended and differential structures that exist in the literature. Specific uses for the equations in this article have been outlined. The L and Q for an example monolithic, differential inductor were extracted from measured two-port S-parameters using equations for differential configurations on low-resistivity substrates.