Stray capacitances of single-layer solenoid air-core inductors

This paper presents a method for predicting parasitic capacitances of solen oid NF inductors made of one layer of turns with circular cross sections, u niformly wound around a cylindrical nonconductive core. The method is based on an analytical approach to obtain the turn-to-turn and turn-to-shield ca pacitances of coils. The influence of the wire insulation is taken into acc ount. An equivalent lumped parallel capacitance is derived. The method was tested by experimental measurements. The calculated and measured values wer e in good agreement in the considered cases. The derived expressions are us eful for designing HF inductors and can also be adopted for modeling and si mulation purposes.