Why are the radar antennas fabricated with net structures?
The requirement of a dish is to be a good reflector at the wavelength for which it is used. When the separation of the net wires or other metallic elements is significantly smaller than the wavelength concerned the wave is almost completely reflected. Therefore, it is profitable to make the antenna lightweight by using wires instead of a continuous metallic surface. The net structure also reduces the wind load on the antenna. Due to this and the overall reduction on structural weight mesh antennas are more easily maneuverable. Most of the radars operate at microwave frequencies. The wavelengths are of the order of several centimetres to tens of metres. It would be stupid to have solid dishes for them.
