Electromagnetic vulnerability testing of aircraft using mode-stirred techniques

Electromagnetic vulnerability (EMV) testing is typically performed on aircraft using a standard method where the aircraft is directly radiated by an antenna, with no mode-stirring. Since a standing wave pattern will cause peaks and nulls in the field inside the aircraft, many antenna aspect angles should be used to assure that all equipment on board the aircraft is exposed to the appropriate field. However, this is very time consuming and often not feasible. As a result, some equipment on the aircraft may not be exposed to the intended field level. Using mode-stirred techniques during EMV testing will provide improvement in field distribution throughout the aircraft so that the need to use several aspect angles would be eliminated, and a more controlled and thorough test would result. This study was performed to demonstrate this, by comparing cable coupling and field level measurements on a P-3 and an E-2C during EMV testing using both the standard method and mode-stirring.