We propose to demonstrate the feasibility of using time domain terahertz measurements to locate, identify and image defects and material variations within advanced composite materials used in missile radomes. We will investigate the time and frequency domain transmission properties of radome materials to determine their intrinsic terahertz electrical properties and prove the detectability of defects. These and other measurements will also be used to prove high-resolution mapping of the composite material structures. We will generate methods to link measured terahertz properties to estimated microwave electrical properties and radome performance. In particular, we will investigate the limits of these methods in enabling rapid estimation of microwave boresight error and transmissivity using measured terahertz maps. We will finally determine the specifications of a prototype automated terahertz missile radome inspection system requiring minimal human intervention. In Phase II, we will deliver a prototype system providing accurate and consistent defect mapping and estimated microwave radome performance.
Benefit: The proposed work is anticipated to enable nondestructive, accurate, and lower cost evaluation of missile radomes through the use of terahertz technology. The work should lead to a prototype terahertz radome inspection system that automates and visualizes defect identification to identify mechanical weaknesses, and generates microwave boresight error correction maps, all at reduced cost. The most immediate beneficiary of the terahertz radome inspection system would be DoD components, particularly the Navy, or their prime contractors. These would serve as the principal customer and commercial application with the goal of replacing more traditional radome inspection techniques. The prototype terahertz inspection system could be later adapted to numerous composite and ceramic inspection roles including quality control for civilian and military aerospace parts, advanced armor, fuel cells, precision bearings, electronics, and photonics. Some potential customers include Boeing, Lockheed-Martin, Raytheon, Northrop-Grumman, Ceradyne, and CoorsTeK.
Keywords: Microwave, Microwave, Dielectric, imaging, defects, Boresight Error, Nondestructive Evaluation, Radome, terahertz
