Investigation of distance dependence of radiated emission test results

Distance dependence of the radiated electric field strength has been investigated using the imitated equipment for which the radiated electric field strength can be calculated. The imitated equipment is presented by a wire-grid model and the radiated field is calculated by the method of moment. The results indicate that the mean value of the relative electric field strength has large deviation from the ideal relationship, and this is caused by that the antenna sweep range is limited for horizontal polarization and the directivity of vertical cross section changes as the angle for vertical polarization. Then, the prediction method of the electric field strength at distance of 10 m is developed, and the evaluation shows that this method is effective at 700 MHz or less