Effects of sensor positions on military radiated susceptibility tests

The MIL-STD 461F RS103 test is one of the essential radiated immunity tests for military equipment. Unlike the pre-calibration method of commercial radiated immunity tests such as EN61000-4-3, the RS103 test requires the placement of an electrical field sensor close to the application point of the EUT (Equipment Under Test) and also requires active-leveling of the field based on the feedback from the sensor without use of a pre-calibrated field. In most cases, the position of the sensor is not certain in the standard and every laboratory uses their own selections for probe positions which are close to the application region. In this research, we showed that the chosen sensor position directly affects the value of power injected into the antenna, consequently affects the test results significantly for a constant electrical field value owing to the reflections coming from the EUT itself.