Function of aircraft Radome

A Radome is the dome-like shell that protects a radar assembly from inconvenient things like weather and moving fast. The radome’s conical shape assists the aircraft’s aerodynamics, and is made of composite materials, usually glass fibre.

Radar assemblies are fragile, moving, and in planes, usually mounted on the front. That's pretty tough to design around for efficient flight.

The open radome of an F-16 Fighting Falcon, showing off the radar (tan flat plate) and the avionics that do all the magic (boxes under the gullwing door).

On planes, radomes tend to be sleek. But fighter planes don't have a monopoly on them! Nose radome on a passenger plane, open to reveal the weather radar.

That dinner plate looking thing is a radome for the massive radar carried by an Airborne early Warning and Control System (AWACS) plane. But it serves the same purpose, protecting its fragile sensor.

The Radome covers the AWS (Airbone Weather Radar) of the aircraft from atmospheric impurities, specially, from water and ice. AWS uses the same principle as a primary radar. It transmits a wave, which gets hit by the target and reflects back. When there is ice, some of the wave energy of the transmitted wave is used to melt the ice and evaporate the resulting water (like a microwave). This results in a weak reflection from the desired target.

The AWS in aircraft is mostly used to detect the size of water droplets in clouds which can be used to measure the level the turbulence. To get better results the wavelength of the waves are quite small at like 3 cm (the diameter of a large water droplet). This means, it operates at quite a high frequency at approximately 9000 Mhz. Hence it is prohibited to operate the AWS near buildings and people.

*Note

The nosecone radome is designed to protect the aircraft’s weather antenna as well as serve as an integral part of the aircraft’s aerodynamic shape. In addition to that, it must also not affect the underlying radar’s signal.

A radome designer must ensure that key performance criteria are met for each of the device’s designated functions no matter what happens during flight.