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Luneberg Lens Technology The
Luneberg lens is scientifically recognized. It is used to enhance
the radar visibility of a target upon which it is installed. For
example a sailboat with a Luneberg lens reflector upon it might
appear on a radar screen as a large ship, or a target drone might
appear as large as an airplane. A Luneberg lens is spherical, consisting of a number of concentric spherical dielectric shells (hemispherical shells in the case of TriLens reflectors). Each shell has a different index of refraction, so that an entering signal will be refracted into a nearly elliptical path to a point on the opposite surface of the sphere (Figure 1). A reflective material located at the opposition point causes a return of the signal, again refracted elliptically through the sphere and out again in the direction it came. A Luneberg
lens performs much as a parabolic reflector, except that whereas
a parabolic reflector is effective along its central axis (M), the
Luneberg lens is an effective retroreflector over a wide range of
entry angels (such as PIXI to P"X" in Figure 1, for example).
The performance in this respect is limited only by the practical
limitations of the reflector geometry.
Fig 1 Signal Path in the Luneberg Lens The
result is a completely passive, reflective device, which concentrates
the reflected energy back in the direction of the incident beam.
The Luneberg lens reflector is built with a spherically shaped reflector
cap as shown in figure 2, indicated by the letter AL Normally these
reflectors will have a conical reflective pattern, with the horizon
cone subtending 120 degree at the MB points. TriLens Radar Reflector
Luneberg lenses are designed for optimum use with a X-band radar,
but they are broad-band devices and also provide useful performance
at other radar frequencies. TriLens Radar Reflector Luneberg lenses
are manufactured to meet military specifications for use in military,
naval, aeronautical and other rigorous applications.
Buoyage
Systems Australia Pty Ltd
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