4. Networks

4.1 Linear networks

Linear networks are mainly used in radar applications:

• or directly for certain applications such as secondary radars (or IFF, Interrogation Friend or Foe) , maritime traffic radars...

• or, more generally, as a component of a more complex structure.

For example, they can be stacked to form a slab antenna, i.e. a planar array. Alternatively, they can be used at the focus of a parabolic trough reflector, to create a mixed antenna. In this case, the wave emitted by the array is cylindrical as long as the distance is much smaller than 2d ² /λ, d being the distance to the array. This wave is transformed into a...