Broadband EC Models of Coil Antennas for Inductively Coupled Systems

Wireless energy and data transfer systems in the near field are mostly based on inductively coupled coil antennas. These systems require accurate coil antenna equivalent circuit (EC) models for an efficient system design. In this work, we present broadband EC models of coil antennas to conduct circuit-level analyses of such wireless energy and data transfer systems versus a broad frequency range, e.g., wireless power transfer (WPT) or near-field communication (NFC) systems. The novelty of the EC models lies in their broadband nature compared to previous work. We provide an approach to model single coil antennas far above their self-resonant frequency with a simple broadband EC model, for analyzing the system’s interoperability or coexistence with other systems. Additionally, we provide a broadband EC model of strongly coupled coil antennas with a particular focus on the modeling of parasitic capacitive coupling, which can severely impair communication system performance. The proposed EC models were developed and verified from 10 kHz up to 100 MHz by measurements and finite element simulations.