Accurate EM simulation of SMT components in RF designs

SMD is designed into many MCM/SiP products, but accurate EM simulation of SMD in a design has been a challenge. In fact, circuit simulation with an EM MCM model connected with vendor-provided SMT models often leads to a shift of harmonic trap notch. Such shift may be attributed to the intrinsic inductance of an EM port. In this paper, we focus on EM models of HFSS, present discovery of intrinsic port inductance in an HFSS model and discuss issues and techniques on how to handle lumped SMT ports in an HFSS EM model for more accurate SMD circuit simulation.