Modeling and Extracting the Nonlinear Input Characteristics of Proximity Coupling Transponder ICs by Utilizing the ISO Measurement Setup

IC input characteristics are important parameters for proximity coupling (13.56 MHz) transponders. Modeled as voltage-dependent capacitor ( $\boldsymbol {C_{ic}}$ ) and resistor ( $\boldsymbol {R_{ic}}$ ) connected in parallel, they are typically measured using an LCR meter. In this work, we introduce a nonlinear, custom-defined circuit component (IC-component) based on LCR meter measurement results that is used within our simulation framework for predicting contactless performance metrics (e.g., minimum operating magnetic field strength $\boldsymbol {H_{min}}$ ). Combined with linear $\boldsymbol {S}$ -parameter models from EM simulations of transponder antennas on a standardized test setup (ISO test PCD assembly), the IC-component is used in nonlinear circuit simulations to predict $\boldsymbol {H_{min}}$ . Due to LCR meter’s input limitations, it is difficult to cover the entire range for predicting certain performance metrics at higher $\boldsymbol {H}$ -levels (e.g., IC robustness). Therefore, we also present a method that utilizes the ISO test PCD assembly and determines IC input characteristics of a transponder DUT. This method ( $\boldsymbol {C_{ic}}$ and $\boldsymbol {R_{ic}}$ extraction method) measures the assembly’s output voltages up to higher $\boldsymbol {H}$ -levels and uses them as input to the system’s linear model. IC input characteristics, obtained as a function of measured voltages, are thereby extended towards higher $\boldsymbol {H}$ -levels and can be added to the IC-component, so that additional contactless performance metrics can be predicted by our simulation framework.