Contents

• • 1 Motivation and Objectives
  • 2 State of the art
    • 2.1 The three-dimensional full wave simulation approaches
      • 2.1.1 Time domain methods
      • 2.1.2 Frequency domain methods
    • 2.2 The semi-analytical approach based on EMI source multipole macro modeling
    • 2.3 Analytical and numerical modeling of the EMI effects to classify sources and coupling paths regarding their potential to exceed emission limits
    • 2.4 Analytical model for the free space radiation of a cubical enclosure intended for fast predesign investigations
    • 2.5 Modeling of the common mode coupling from ICs to the cavity field
  • 3 Electromagnetic emissions mechanisms from PCBs
    • 3.1 Conducted emission - Radiated emission
    • 3.2 Direct radiation from PCB sources
      • 3.2.1 Direct radiation from trace and IC package loops on the PCB
      • 3.2.2 Direct radiation from plane edges on the PCB
      • 3.2.3 Direct radiation from a PCB which is parallel to a metallic cover plane at an electrically short distance
    • 3.3 Emissions through galvanic coupling, electric and magnetic near field coupling to cables, long nets, and mechanical structures, interpreted as antennas
  • 4 Cavity model of the electromagnetic field between PCB and metallic cover
    • 4.1 Derivation of the two-dimensional Helmholtz equation model
      • 4.1.1 Boundary condition at the edges of the parallel planes
      • 4.1.2 Summary of the cavity model equations
    • 4.2 Analytical solution methods for the two-dimensional Helmholtz equation
    • 4.3 Inductance, capacitance, resistance (LCR) grid solution method for the two-dimensional Helmholtz equation
    • 4.4 FEM solution for the two-dimensional Helmholtz equation
  • 5 Introduction of sources and PCB layout structures to the cavity model
    • 5.1 Calculation of K_couple with mode decomposition
    • 5.2 Expression of K_couple by a distance ratio factor
    • 5.3 Validation of the trace introduction by HFSS^® simulations
    • 5.4 Independence of the common mode coupling from the horizontal trace routing
    • 5.5 Link of the common mode coupling to the near field above the PCB
      • 5.5.1 Prediction of mTEM IC measurements from near field scan data.
      • 5.5.2 IC EMC model validation with near field scan data
      • 5.5.3 Behavior modeling of geometrically complex components
    • 5.6 Modeling the coupling from integrated circuits
    • 5.7 Link to the current driven common mode mechanism and the common mode inductance of a trace inside a cavity.
    • 5.8 Design consequences
    • 5.9 Necessity to consider the influence of the external environment at the cavity field simulation
  • 6 Domain decomposition with PMC boundaries and port interfaces
  • 7 Analytical model for the radiated emissions from the slot of a rectangular enclosure:
    • 7.1 Analytical cavity model for a rectangular enclosure with three closed edges and one open slot
      • 7.1.1 Derivation of the cavity model with the separation method
      • 7.1.2 Summary of the analytical cavity model of the rectangular enclosure with a slot on one edge
      • 7.1.3 Interpretation of the analytical model
    • 7.2 Analytical consideration of the radiation loss and a model for the free space radiation from the enclosure slot
      • 7.2.1 Calculation of the far field from the slot field distribution
      • 7.2.2 Derivation of an admittance matrix for the consideration of the radiation loss at the cavity field simulation
      • 7.2.3 Introduction of the radiation loss admittance matrix into the cavity model matrix
      • 7.2.4 Summary of the equations for the introduction of the radiation loss into the cavity model and the far field calculation
    • 7.3 Comparison of the analytical model results to HFSS^® simulations and measurement results
    • 7.4 Radiation diagrams for the rectangular enclosure with a slot on one edge
  • 8 Design rules for PCBs inside a metallic enclosure with apertures
    • 8.1 Rule 1: Trace placement symmetric to the enclosure symmetry reduces the coupling up to the second enclosure resonance
    • 8.2 Rule 2: Trace placement parallel and close to metallic enclosure walls reduces EMI, trace placement orthogonal and close to enclosure walls increases EMI
    • 8.3 Rule 3: Trace placement in the middle of the enclosure slot reduces the EMI at the first resonance
    • 8.4 Rule 4: Reduction of the trace height d above the ground plane reduces EMI
    • 8.5 Rule 5: Single source placement closer to an enclosure wall reduces EMI
    • 8.6 Rule 6: Shielding reduces the common mode coupling
    • 8.7 Rule 7: A ground plane under an IC reduces EMI
    • 8.8 Summary of the design guidelines
  • A. Validation of the analytic common-mode coupling factor d/h
    • A.1 Variation of the trace position
    • A.2 Variation of the enclosure height and the trace height above the ground plane, comparisons of the transfer impedance for parallel planes with four open edges and comparison of the transfer impedance for the two different trace routings in Figure 5.7
  
  
• Bibliography

C. Poschalko: The Simulation of Emission from Printed Circuit Boards under a Metallic Cover