T18.2 - Electrical Model and Characterization of Near-Field Antennas for Communications from Induction Cooktop

Induction cooktops are increasingly popular, serving as wireless power sources in the range of several kW. This operation requires communication, for which the Ki standard specifies near-field coupling (NFC) at 13.56 MHz. The performance of NFC antennas is compromised when they are integrated into a cooktop due to the presence of components such as ferrites, planar coils, and shielding plates. These elements significantly affect the antenna’s frequency-dependent impedance, potentially causing a mismatch that hinders effective communication. This work analyzes the influence of these components using finite element analysis (FEA) with COMSOL Multiphysics. It then proposes an equivalent electrical circuit model to represent the antenna's frequency-dependent behavior accurately. The model, consisting of parallel RLC circuits, was fed with measured values to reproduce experimental data. While the model successfully described the initial resonances, it was less effective at capturing smaller resonances at higher frequencies. Despite this, the model reasonably reproduced the general experimental trend and successfully predicted the main resonances.