Physics-Based Dipole Moment Source Reconstruction for RFI on a Practical Cellphone

A physics-based dipole moment source reconstruction is proposed to estimate the near-field coupling between a liquid crystal display panel to a cellphone's cellular antenna. Based on the understanding of the current distribution on the source, a magnetic dipole moment source is reconstructed to replace the real radiation source that is located at the edge of the flexible printed circuit board. To characterize the coupling from the equivalent dipole moment source to the victim antenna, the noise transfer coefficient is proposed. The noise transfer coefficient can be calculated from the near-field scanning and the direct coupling measurements using a wideband source. The proposed physics-based dipole moment source reconstruction and noise transfer coefficient are successfully validated through the measured near-field coupling in a practical cellphone.