Analytical Technique for Evaluating Stray Capacitances in Multiconductor Systems: Single-Layer Air-Core Inductors

This paper presents a procedure for evaluating self-capacitances and parasitic capacitors between physically adjacent turns in multiconductor systems-with a special focus on single-layer air-core inductors. To this end, the paper proposes the use of standard cells, which correspond to a minimal and basic turn, layer, or macrolevel arrangement of a winding in reference to its patterns of stored electrostatic energy. A standard cell embraces mathematical rules derived by means of a curve fitting approach through a set of finite element analysis (FEA) simulations. Besides, it is applied in a matching routine wherein self- and stray capacitances are evaluated according to the relative position of each turn, layer, or macrolevel arrangement along the length of the winding. Finally, the analytical technique is validated by comparing frequency-domain results obtained from an implemented SPICE model and laboratory measurements.