Influence of Dielectric Permittivity on Radiated Immunity in Real and Emulated Far-Fields

This paper presents the impact of dielectric permittivity on radiated immunity of integrated circuits (ICs) in far-field, extending in detail a technique recently proposed by the authors. To this end, the IEC 10 cm 10 cm square PCB with an equivalent patch as a rough approximation of an IC was considered in two different far-field conditions: (1) on a TEM cell aperture, and (2) in a far-field zone of a radiating antenna. In (2), the PCB was considered in horizontal and vertical orientations. The patch was then loaded by small solid piece of demetalized low-loss substrate of two different relative permittivities to examine the load presence influence on the radiated immunity. The wave impedance was used as the criterion. Results show that, in both cases, the load presence lowers the wave impedance, disregarding the PCB orientation with respect to the antenna in scenario (2). Moreover, no improvements due to the variation of the load permittivity value were observed in the E / H ratio distribution in a TEM cell similar to those obtained with the PCB oriented perpendicularly to the antenna in a real far-field zone. In the case where the PCB is parallel to the antenna, further improvement in the wave impedance was observed for a loaded PCB with a higher permittivity value.