Repeatability and reproducibility of radiated immunity tests

The present definition of Uniform Field Area (UFA) specified by EN 61000-4-3 does not provide constraints sufficient to guarantee reproducibility. It may be useful to establish a standard adequate for test repeatability when tests are performed in the same test site. On the other hand one is induced to believe that meeting the radiated test uncertainty calculated on the basis of the test equipment performance characteristics is sufficient to cover the needs of repeatability and reproducibility but this is not completely true because the electric field uniformity is not taken into account. This paper defines the Uniform Field (UF) factor; it is the right parameter to monitor and control the uniformity of the electric field in the test zone. This factor can be used to compare the results of tests of the Device under Test (DUT) performed in different test sites.