Calculation of radiating magnetic field from indoor AC mains cable using four-port network

Recent progress in home networks is increasing the interest in high-speed power line communication (PLC). This has the advantage of not needing the installation of new communication cable. However, the electromagnetic field radiating from the cable could disturb other radio communication systems. Thus, the field radiated from the cable should be evaluated In this paper, a pair of conductors of an indoor AC mains cable and its ground plane were represented by four-port networks and the common-mode current was calculated. In the calculation, the capacitance between conductors and between one conductor and the ground plane were obtained from numerical calculations to consider the effect of the cable insulator. The radiated magnetic field was calculated from the common-mode current distribution along the cable. The magnetic field radiated from a 4-m-long indoor AC mains cable was measured in an anechoic chamber to evaluate the validity of the calculation model. The results indicate that the deviation between the calculated and measured values was within 4 dB, and the radiated magnetic field strength was almost in proportion to the longitudinal conversion loss of an AC mains line. The calculation method was applied to an AC mains line with branches and the results almost agreed with the measured ones.