Modeling of radiated immunity measurements by an active two-port model

In this paper a new approach of modeling radiated immunity tests by an active two-port model is shown. The goal of this approach is to simplify analysis of different test configurations by separating disturbance generation and device under test (DUT). With this approach information about the real level of disturbance generated at the end of the perturbed wire in a radiated immunity measurement can be determined for different DUTs. To generate this active two-port model, MoM simulations of field to wire coupling are done, with special emphasis on modeling a typical log-periodic dipole array antenna structure (LPDA) instead of a planar incident wave. To verify the simulations, s-parameter measurements of an according setup are done. Both, simulations and measurements can be used to generate an active s-parameter model of the immunity test setup. The model is then applied to determine the generated disturbance - in terms of forward power into any arbitrary load at the end of the irradiated wire. This finally allows comparing the radiated immunity test to other immunity tests, e.g. Direct Power Injection (DPI) immunity measurements.