Skip to comments.Device Turns Flat Surface into Spherical Antenna
Posted on 04/15/2014 2:55:47 PM PDT by BenLurkin
The new lens, described in AIP Publishing's journal Applied Physics Letters, was fabricated by Tie Jun Cui and colleagues at Southeast University in Nanjing, China and is an example of a metasurface or metamaterial -- an artificial material engineered in the lab that has properties not found in nature. In this case, by coating the surface with the tiny U-shaped elements, it acquires properties that mimic something known as a Luneburg lens.
First discovered in the 1940s Luneburg lenses are traditionally spherical optics that interact with light in an unusual way. Most lenses are made of a single material like plastic or glass that bends light passing through in a consistent, characteristic way -- a key characteristic of the material, which is called its "index of refraction."
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Where can i get one?
the technical article was talking about invisibility. I can see it now, kids running an antenna out on their 3D printer and disappearing.
A Luneburg lens antenna offers a number of advantages over a parabolic dish. Because the lens is spherically symmetric, the antenna can be steered by moving the feed around the lens, without having to bodily rotate the whole antenna. Again, because the lens is spherically symmetric, a single lens can be used with several feeds looking in widely different directions. In contrast, if multiple feeds are used with a parabolic reflector, all must be within a small angle of the optical axis to avoid suffering coma (a form of de-focussing). Apart from offset systems, dish antennas suffer from the feed and its supporting structure partially obscuring the main element (aperture blockage); in common with other refracting systems, the Luneburg lens antenna avoids this problem.
Back in the day it was one of my steel coat hangers twisted up into a circle shape! Don’t laugh, those things worked great on the old Black and Whites!
So that’s what I was doing wrong. Thought I just had to shove that thing into where the other one snapped off.
BTW, knew a guy who used a potato for his car’s replacement antenna. He claimed it worked just fine.
A ‘tater!!? Damn! About car antennas, remember the old orange 76 ‘Antenna Balls’? They stayed on pretty good until the neighborhood kidlettes did the Swiss Cheese number on ‘em with their BB Guns!!