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

Abstract

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 electro-magnetic cell and the hybrid coupler are mismatched which introduces an error in the measured results. 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 results 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.

Multisegment Multiconductor Transmission Line Model of High-Current Card-Edge Connectors With Analytically Calculated Model Parameters

“…Cavity-mode resonances can be suppressed by adding stitching vias that connect the two layers [32]. Stitching vias are used in the backplane and con-nector boards in [16] and [17] and no resonances are seen there.…”

“…The usage of the two connectors is proposed in [15] to enable measurements of the magnetic field component normal to the printed circuit board (PCB) plane. The connectors are used in [16] and [17] to characterize the radiated EM emission of two synchronous buck converters. The purpose of the connectors is to position a converter inside the transverse electromagnetic (TEM) cell in multiple, well-defined orientations relative to the septum of the TEM cell, and to provide the control signals and the supply and load to the converters.…”