Windscreen Shield Monitor Usng Spiral Transmission Lines

Many aircraft are hardened against the effects of various forms of high power electromagnetic waves, including Electromagnetic Pulse (EMP), High Power Microwaves (HPM), High Intensity Radio Frequency (HIRF), and lightning. These aircraft typically have electrically conducting coatings on their windows, with conducting gaskets that form an electromagnetic seal with the fuselage. These gaskets wear out over time, and must be periodically replaced. We consider here methods for testing the integrity of these gaskets. Gasket integrity is normally tested by placing an RF source on the exterior of the window, and checking for leaked fields on the interior. In principle, this is a straightforward process; however, newer aircraft present some challenges. In some cases, one must remove a significant amount of molding to get access to the interior of the windscreen in the cockpit. A simpler process could save considerable time and reduce the cost of testing. To address this challenge, we propose the use of a Spiral Transmission Line (STL) to detect the presence of fields leaked into a cockpit from damaged electromagnetic gaskets. To excite the field on the exterior, one would use a stripline “blanket,” which is an approximate TEM transmission line. BENEFIT: This research will lead to a design for a windscreen shield monitor that will be far more convenient to use than currently available designs. Simplifying the process will reduce the cost, and will also reduce the time the aircraft is down for maintenance. It may also increase the frequency of testing, which will increase the reliability of the shield. This makes the aircraft less vulnerable to electromagnetic pulse, lightning, or intentional electromagnetic interference. A prototype of the shield monitor will be built during Phase II, and it will be tested on aircraft. If this research is successful, then Phase III would involve using the proposed shield monitor in existing aircraft. It would also be ready to incorporate in to future aircraft, as required. It would also lead to new tests to verify the integrity of shielded doors and windows.