Analysis of the electromagnetic emission of a railway vehicle according to the EN 50121-3-1 standard: a case study

We present a case study on the evaluation of the radiated emission from a railway vehicle according to the EN 50121 standard. Measurements were performed in an open-area test site in two conditions: stationary mode and slow-moving mode, according to the technical document EN 50121-3-1:2018. Magnetic and electric field strengths were measured and compared with limit curves. The considered frequency range is from 150 kHz to 1 GHz. We exploit a time-domain analysis implemented with an EMI receiver, instead of a conventional swept frequency analysis, in order to reduce ambient noise variation, according to CISPR 16-1-1. The usage of a hybrid antenna is proposed to reduce the time needed to cover the 30 MHz to 1 GHz frequency range. We discuss the difficulties resulting from the contribution of external sources, which could be suppressed by performing the measurements in a suitable semi-anechoic chamber, such as the one available at the Laboratories of the Italian Railway Infrastructure Manager (RFI) Osmannoro location. We provide evidence that emission measurements performed in such semi-anechoic chamber yield results in agreement with those obtained in an open-area site.