Advantages of Luneburg Lens | disadvantages of Luneburg Lens Antenna

This page covers advantages and disadvantages of Luneburg Lens Antenna. It mentions Luneburg Lens advantages or benefits and Luneburg Lens disadvantages or drawbacks.

What is Luneburg Lens?

Introduction:
• The spherically symmetric lens with variable index of refraction is known as Luneburg lens. The antenna which is constructed using such lens is called Luneburg lens antenna.
• This antenna radiates beam in any direction for a feed located opposite the beam.
• Feed phase center is located either on the surface of the lens or a short distance away.
• Luneberg lens antenna can be realized as a full sphere or as a hemisphere. Both of these types are shown in the figure.

• The index of refraction when feed is located on the outer surface of the sphere is expressed as follows.
• n = [ 2 - (r/a)²]^0.5
Where,
a = lens outer radius
r = lens inner radius

Benefits or advantages of Luneburg Lens antenna

Following are the benefits or advantages of Luneburg Lens antenna:
➨It helps in scanning beam very rapidly by moving light weight feed around the sphere or by way of switching between multiple feeds.
➨It has many benefits over parabolic dish antenna. It is easy to steer antenna by moving feed around the lens without physically rotating the whole antenna unlike parabolic dish antenna.
➨As luneberg lens is spherically symmetric, a single lens can be used with several feeds looking in widely different directions unlike parabolic reflector in which multiple feeds are used within small angle of optical axis.
➨It offers broadband operation.
➨It is manufactured using inexpensive dielectric materials. It does not use any active elements. Hence this luneberg lens antenna is less expensive.

Drawbacks or disadvantages of Luneburg Lens antenna

Following are the drawbacks or disadvantages of Luneburg Lens antenna:
➨It helps in generating multiple beams by feeding lens from various places. There is only restriction which is blockage due to other feeds or support structures.
➨Its size is large.
➨It incurs relatively large dielectric losses.
➨It is complex to fabricate.