Modeling of the coupling phenomenon between a transmission line and a near-field excitation

In this paper, the coupling phenomenon between the electromagnetic near-field stress and the micro-strip lines connecting the SiGe Heterojunction Bipolar Transistor (HBT), are evaluated by electromagnetic and electrical simulations. A complete electrical model of an electromagnetic near field setup is presented. Each part of this model (injection probe and Printed Circuit Board) are characterized and modeled thank to the ADS software. Comparisons are given between the induced voltage obtained by the electromagnetic simulator HFSS and the induced voltage obtained by using the electrical ADS model, validate the complete electrical model. The originality of this study comes from the generation of a localized electromagnetic field using the near field bench to investigate the reliability of the SiGe HBT. After stress the DC and the high-frequency characteristics are affected by aggression. The comparison between the Direct Power Injection and the near field stress effects indicates that the probe/micro-strip line coupling phenomenon is responsible for the near field stress effects.