Near field noise source reconstruction using equivalent field box for RF desensitization analysis

This paper presents a novel method for noise source reconstruction using an equivalent field box based on magnitude-only near-field data. The proposed approach overcomes the limitations of conventional dipole moment-based methods, which struggle to resolve weak noise sources and unclear near-field patterns in practical devices. The noise source is modeled based on the Huygens' box equivalent principle. To facilitate practical implementation, only the tangential field on the upper surface of the equivalent field box is required. Near-field scanning techniques were employed to measure the magnetic field distribution above the noise source, as captured by a spectrum analyzer (SA). By analyzing the near-field pattern and leveraging a physical understanding of the radiation mechanism, the phase information was assigned through the near-field induced by an ideal Pz dipole, which can be analytically calculated. The proposed noise reconstruction method was experimentally validated across five commercial platforms. The method reconstructed the noise source, imported the equivalent field box into Computer Simulation Technology (CST) with a full-wave receiver model, and achieved simulated coupling at the receiver with an error of less than 5 dB compared to measured data.