Phase Resolved near Field Dipole Reconstruction for Multilayer Board Far Field Escape Prediction
Phase-resolved near-field dipole reconstruction predicts far-field escape emissions within 2 dB, eliminating un-phased scan errors before SAC testing.
Dyadic Greens Function
Field Propagator
Electromagnetic field equations calculate the spatial distribution of radiation generated by distributed current sources. The dyadic greens function mathematically relates the vector electric currents on a printed circuit board to the resulting vector electric fields in three-dimensional space. This function is the mathematical foundation for electromagnetic compatibility simulation tools that predict radiated emissions from trace loops.
The formulation assumes a linear, isotropic medium and stops applying if the material displays non-linear polarization under high field intensities.
Emission Analysis
Spatial integration of surface currents allows electromagnetic compatibility scanning to determine whether a printed circuit board complies with radiated emissions standards. By applying the dyadic greens function to the measured or simulated current distributions on a microstrip line, engineers can calculate the field strength at a standard distance of three meters or ten meters. This computation helps isolate localized board regions that violate emission limits before physical shielding is designed.
The calculation requires accurate knowledge of the dielectric properties of the substrate, meaning that variations in glass weave or resin content can introduce errors in the predicted field strength.
Boundary Evaluation
Verification of the mathematical boundary condition ensures that the calculated field satisfies radiation conditions at infinity. If the substrate borders an infinite ground plane, the function accounts for image currents directly without requiring explicit mesh generation for the metal layer. This simplification reduces the computational workload during the automated design rule check phase.