Broadband measurement of the magnetic moment normal to the printed circuit board plane using TEM cell and phase information

In this paper the measurement of the magnetic moment normal to the printed circuit board (PCB) by a Transverse Electromagnetic (TEM) cell is presented. The PCB is placed inside a TEM cell perpendicular to the septum by using two boards: a motherboard and a daughterboard. The daughterboard represents the PCB and device under test (DUT). An edge connector is vertically mounted on the motherboard to enable the placement of the daughterboard inside the TEM cell and to enable the communication between the daughterboard and the outside world. The phase information is used to distinguish between the magnetic and electric moments without using a hybrid coupler. The absence of the hybrid coupler allows to perform the measurements over a broad frequency range. The method is validated by measuring the PCB circular current loops and by comparing the results to the theory and a very good match is obtained. The complete test system consisting of the TEM cell and the loops is simulated in a full-wave electromagnetic solver and a very good match is obtained, too. The full-wave simulations are used to investigate the limitations of the presented method.