A Calculation Method for Reconstructing Radiation State of PCB Using Known Magnetic Field Amplitude Information

— Using magnetic field data to characterize the state of radio frequency (RF) printed circuit board (PCB) has been widely used in circuit state detection and fault identification. However, it may be difficult to measure the complete state of magnetic field radiation, so the characteristics of PCB may be challenging to establish, which makes the calculation method of reconstructing other radiation information of PCB with existing magnetic field information urgently needed. Based on the basic radiation principle of the electromagnetic field, we propose an algorithm that has advantages in reconstructing the magnetic field radiation state, in which the new single-layer iterative (NSLI) algorithm provides a more reasonable optimization range and field-source conversion matrix for the hybrid particle swarm optimization (HYPSO) algorithm, and converts the inverse problem of the large matrix into a forward optimization problem, further ensuring the accuracy and objectivity of the algorithm. According to the known magnetic field amplitude, this article uses a two-phase drive (TPD) circuit at 50-MHz frequency as a device under testing (DUT) to verify the proposed algorithm’s feasibility by reconstructing the complete 3-D magnetic field component radiated from the DUT and estimating the unknown magnetic field amplitude on the predicted plane. The specific experimental data show that when the magnetic field amplitude is known, the relative errors of the reconstructed magnetic field on the x-, y-, and z-components are 1.9%, 0.02%, and 0.06%, respectively. In the meantime, under the actual measurement environment with a maximum relative uncertainty of 0.59%, the relative error of the magnetic field amplitude of the unknown predicted plane is 6.15%.