Coupling onto radio frequency components enclosed within canonical structures.

Abstract

An efficient and accurate hybrid modeling is presented for the analysis of electromagnetic interference (EMI) effects on RF/microwave components enclosed within multilayer cavities. The method of moments (MoM) is employed in conjunction with rigorous modal Green's function (GF) (the MoM-GF technique) to account for EM interactions within rectangular cavity enclosure containing typical microwave structures. We considered structures with wire configurations and multilayer printed circuit boards (PCBs) that support possible devices such as filters and amplifiers. For the analysis of enclosed cable and wire configurations, a challenge was the convergence of the associated moment method matrices and two approaches are presented. One is based on the Kummer's transformation technique to accelerate the sum associated with the double modal series used in the representation of the cavity GFs. The other is a hybrid method utilizing a two-step decomposition to account for the interactions between enclosures and internal conductors. Rigorous analysis of multilayer printed circuits within cavity enclosures with multiple apertures and penetrating cables is considered. As part of this study, a process is developed to account for the interactions of vertical and planar currents within a multilayered substrate configuration enclosed within the structure using efficient and rather fast matrix element evaluations. Using this procedure, EMI effects through multiple apertures are investigated via a parametric study for different circuit geometries and lumped loads. For the analysis of PCBs within a multilayered and possibly cascaded multi-cavity configuration, a simple aperture coupling method is developed. This approach allows for the concurrent analysis of a large number of vertical connections and planar metallization within each layer interface. An important component of the proposed EMI investigation is the evaluation of coupling on the PCBs in the presence of active RF circuits such as power amplifiers. This is done through a decomposition approach that integrates the MoM-GF technique with a SPICE-like circuit solver. The validity and flexibility of the proposed modeling technique is demonstrated for various cavity geometries and internal printed circuit components subject to external EM illuminations.