Antennas in the wild: aviation & radar

The same principles scale up to the large, mission-critical systems you see at any airport.

Surveillance radar

An airport surveillance radar (ASR-9, ASR-11) is a rotating reflector that paints aircraft with a narrow S-band fan beam, using circular polarization to see through rain. Riding on top, the secondary surveillance array interrogates aircraft transponders for identity and altitude.

Navigation aids

A VOR lets aircraft read their bearing from a station using a clever rotating phase pattern. For landing, the ILS localizer array defines the runway centreline and the glideslope antenna projects the correct descent angle using ground reflection.

The takeaway

Beamwidth, gain, polarization, resonance — every concept from this curriculum is at work in these systems. Once you can read an antenna’s shape, you can read what it is for. Explore the linked antennas to see each one in detail.