Measurement Validation for the Extension of Emission Measurements in Alternative Test Sites Above 1 GHz

Abstract

Measurement procedures for determining the radiated disturbances from electronic equipment are described in several IEC/CISPR standards and are well probed for frequencies up to 1 GHz. Above that frequency, radiation pattern of EUTs evolve complex forms so that the direction and magnitude of the maximum directivity is not known by design. Hence, standardized sampling approaches might underestimate the "true" maximum of the radiated emission. In this paper, an extension of these measurement procedures is proposed. The method uses a stochastic approach for estimating the maximum directivity based on the electrical size of the EUT. This is combined with a total radiated power measurement for a reduced sampling procedure to predict the maximum free-space, far-zone electric field. For validation purposes, an extensive 3-D scan of the radiation pattern of a generic EUT is performed. Different subsampling approaches are then investigated while the new prediction method is applied. It can be shown that the accuracy of the measurement procedures can be increased due to the proposed method.

A Review On Links Between Different EMC Test Environments in Medical Technologies

“…In [17], an extension of emission measurements above 1 GHz for alternative test methods was presented in the case of unintentional EM radiators. The prediction approach had also led to an overestimation of the maximum, while standard sampling approaches might underestimate the true maximum (due to the limited, specific number of sampling points) An experimental validation for their proposed extension to emission measurements can be found in [18]. However, to the best of the authors' knowledge, little or no published work relating to the correlation between AC (SAC or FAC) and uncontrolled environments is available in the current literature.…”

Electromagnetic fields in reverberant environments

“…Similarly to small scale fading in radio communications, approximating the data with an exponential curve, using even a very low amount of measurement points, can significantly lower the error with respect to a single measurement. Further approximations, also related to the limited amount of measurement angles and the estimation of the radiation pattern, can be made using the unintentional radiator principle [70]. However, due to the high amount of simplifications and mistake possibilities, the modification suggested here requires more attention and deeper analysis.…”