NIST performs electromagnetic shielding effectiveness tests on a commercial aircraft. (News Briefs).

NIST recently performed electromagnetic shielding effectiveness tests on a commercial aircraft using NIST designed broadband horn antennas and specialized time domain measurement methodology. The information gained in this effort is being used to develop low-cost and efficient measurement techniques for in situ testing of aircraft.

Shielding effectiveness measurements are performed to quantify the electromagnetic fields coupled into an aircraft from an external source, or conversely, internal to external coupling. It is best is to measure an aircraft at an open area test site. However, taking an aircraft out of the production chain is extremely costly for the aircraft industry. Continuous wave measurements made in a hanger or production facility suffer from unwanted reflections that make data interpretation difficult. Thus, the aircraft industry is interested in time domain methods that enable extraneous reflections due to hanger walls to be windowed out using gating techniques.

NIST engineers used time domain methodology developed at NIST to measure an aircraft in a paint hanger along the production line. In addition, NIST has developed a joint time-frequency analysis tool that will be used to extract critical cavity decay characteristics useful in aircraft shielding studies. The Naval Surface Weapons Center and a private company sponsor this effort.

CONTACT: Robert Johnk, [phone]; [e-mail].