Evaluation of Radio Frequency Immunity Test Facilities Based on the Scattered Field of a Conductive Sphere.

In the radiation immunity test for telecommunication equipment, an electromagnetic applicator such as chamber, a transmission electron microscopy (TEM) cell and a general transmission electron microscopy (GTEM) cell are used. Characteristics that include a semianechoic uniformity of the electromagnetic field without a device under test have been evaluated. However, characteristics that include an electromagnetic field in the presence of the device under test have not been reported. In this paper, it is recognized that these electromagentic application are designed in such a way that they can generate an electromagnetic field distribution generated by the plane wave incident on a conducting sphere, the electric field is evaluated and compared in the case in which the device under test is placed within the application. Further, evaluation results are include for the size of the device under test for which the immunity test is possible in each applicator. The evaluation method first derives the theoretical value of the scattered electric field when a plane wave is incident on the conducting sphere in free space. Next , these theoretical values are compared with the measured electric field values around the conducting sphere in each electromagnetic applicator. It was found that the difference between the measured and the theoretical results is the smallest and the frequency dependence is the lowest in a semianechoic chamber. In the case of a TEM cell and a GTEM cell, it was found that the difference between the measured and the theoritical values is less than +6 dB if the magnitude of the device under test is less than one-third the spacing between the inner and outer conductors. [ABSTRACT FROM AUTHOR]