Fast impedance formulation and numerical computation associated with ratios of confluent hypergeometric functions

In modeling of hard disk drive interconnects, one often encounters frequency-dependent impedance expressions formulated in terms of special and transcendental functions or symbolic inverses. In this paper, we develop fast accurate evaluations of these expressions with solution visualization and correct interpretation. We demonstrate this methodology for the computation of a ratio of confluent hypergeometric functions via Pade approximations for a number of geometrical structures such as a round wire and a flat plate. Equivalent circuits are also derived.