Interestingly, Pendry’s work on metamaterials started when he was working for Marconi. He was looking at the application of carbon fiber for a stealth coating when he realized that its interaction with radar was determined by the length of the fibers – it was effectively acting as an array of tiny aerials – and that the same effect could have many other applications.
Invisibility in the optical spectrum will be challenging because metamaterials will need to be constructed on a scale corresponding to the wavelengths of visible light, which is just a few hundred nanometres. That technology will not be around for at least five years.
But radar invisibility is much easier because radar wavelengths are in the centimeter range. Pendry’s colleague, Dr. David R. Smith at Duke University, is already working on a microwave metamaterial. Results are expected within eighteen months.
Unlike existing stealth techniques, a metamaterial should in principle be able to make an aircraft (or missile) literally invisible to any radar from any aspect.
