Electromagnetic environment threat level requirement for military aircraft susceptibility testing in support of high intensity radiated field qualification

The UK have a requirement to establish Electromagnetic Environment (EME) threat levels, covering the frequency range 790 MHz to 50 GHz, on which to base investment in a radiated susceptibility Electromagnetic Environmental Effects (E3) High Intensity Radiated Field (HIRF) test system for military aircraft. Numerous international standards specifying EMEs were initially reviewed but were found to differ significantly in terms of stated EME magnitudes. In addition, they did not address the parameters of Pulse Width (PW), Pulse Repetition Frequency (PRF) and Duty Cycle (DC), which are considered important for avionic system testing, because such data is often classified. The resulting assessment presented in this paper combines both a review of the EMEs, based on established UK and international standards, with a detailed assessment of world-wide threat transmission parameters in order to address the PW, PRF and DC parameters. Assessing the threat parameters includes addressing near and far-field electromagnetic propagation from microwave transmission antennas. Finally, the required parameters for the HIRF EME are declared.