Improved Estimation of Radiated Fields of Unintentional Radiators by Correction of the Impedance Mismatch Between a Transverse Electromagnetic Cell and a Hybrid Coupler

摘要

Radiated fields of unintentional radiators can be estimated from the measurements performed by a transverse electromagnetic cell. A hybrid coupler connected to the outputs of the transverse electromagnetic cell separates the electric and magnetic coupling, which allows to calculate the generated far-field radiation consistently. However, the transverse electromagnetic cell and the hybrid coupler are mismatched. The mismatch introduces an error in the measured data. The error of up to 8.5 dB is obtained in the measurements of the small loop. The impedance mismatch is dominantly a consequence of the phase shift, which is related to the propagation of the signal through the measurement setup and which is present even if all elements of the measurement setup are ideal. The methodology for correcting the measured data is proposed and it is validated on the measurements of the small loop. The methodology is applied to the measurements of two synchronous buck converters and their radiated fields are estimated.