A numerical technique is presented for the determination of the performance of magnetically coupled coils for use in medical telemetry systems. These telemetry systems are used to established bidirectional communication links between an implant and an external instrument in order to obtain diagnostic information. The technique is based on a general formulation and solution of the partial differential equation describing the electromagnetic field problem associated with these system. It uses variational techniques in conjunction with the two-dimensional finite-element method. The performance parameters that are determined and tested include: coil performance measures, reflected voltages for the implant, the effect of induced eddy currents, and displacement currents and geometry changes in the telemetry region.
