Directional properties of the Bilog antenna as a source of radiated electromagnetic interference measurement uncertainty

The influence of the wideband Bilog antenna directivity on uncertainty in radiated electromagnetic interference measurement was analysed. Since the position of the antenna varies with respect to the measured equipment during measurement, the incidental angle of the measured electromagnetic wave also varies. In this manner, errors of antenna directivity occur when using non-dipole antennas, such as the Bilog. An analysis of errors was executed by means of a numerical simulator of the electromagnetic field. Therefore the authors need to find a model capable of reproducing enough of the properties of the real Bilog antenna. On the basis of this model, the authors investigated the directional properties of the Bilog antenna and how they vary with frequency and with the presence of other subjects, such as ground plane, antenna mast, and so on, in the antenna´s surroundings. The directivity of the Bilog antenna as one of the possible sources of measurement uncertainty is evaluated here.