What is an Antenna Radome?

An Antenna Radome is a structural, protective enclosure that is used to protect an antenna. It is constructed with a material that minimally attenuates the electromagnetic signals transmitted or received by the antenna. Radomes are used to protect the surfaces of antennas from harsh weather and environmental conditions. They are also used to conceal the antenna’s electronic equipment from public view for security purposes. In addition to this, radomes are useful in situations where rotating antennas might accidentally collide with other nearby objects or equipments, resulting in damages. In such cases, radomes form a protective enclosure that conceals these rotating antennas, thereby protecting both the antenna as well as other nearby objects from potential damage. 

Antenna Radomes can be designed in different kinds of shapes, sizes, and construction materials according to the intended application. Some common shapes used in the industry exist, which include spherical, geodesic, and planar. The various construction materials used more commonly are fiberglass, polytetrafluoroethylene (PTFE)-coated fabric, and others.

Today, radomes are used as weatherproof, protective enclosures serving both antenna as well as the complete radar module consisting of the transmitter, receiver, and antenna. In airborne applications such as in a fixed-wing aircraft, the nose cone-shaped enclosure acts as the radome. Rotating antennas are found in airborne early warning and control (AEW&C) which are covered by a radome, which results in a rotating radome or rotodome. The radome is typically mounted on top of the fuselage to provide full 360˚ coverage of the view. Other newer AEW&C radar systems also exist, which integrate three antenna modules within a radome. Similar to rotating radomes in aircrafts, they are also mounted atop the fuselage for 360˚ coverage. For instance, the Chinese KJ-2000 and India’s DRDO AEW&Cs radar systems integrate radomes in such manner.

Structure of an Antenna Radome

An antenna radome typically consists of an antenna mounted on a flat surface, a metal cavity base located underneath to support the entire structure, a semi-spherical glass lens (an optional inner layer below the radome to improve the antenna gain), and finally, the outer protective layer, usually a fiberglass or PTFE. The below figure illustrates the structure.

            Structure of an Antenna Radome, Image Credit: COMSOL

Types of Radomes

While radomes are designed with varying shapes, sizes, and types of material. There are three major types of radomes (ground) used worldwide. They are composite radomes, air supported radomes, and space frame radomes.

1. Composite Radomes/Rigid Self-Supporting Radomes: Composite Radomes are radomes that consist of a rigid, self-supporting shell type structure constructed using doubly-curved panels, resulting in a spherical-shaped dome.
2. Space Frame Radomes: These radomes consist of a rigid, self-supporting structure that is composed of triangular panels arranged in a geodesic shape.
3. Air-Inflated Radomes: These radomes have a flexible fabric envelope or shape that is always inflated with air at all times. The operation of this radome is dependent on a un-interruptible power supply along with redundant air blower systems.

Applications of Radomes

Stationary Antennas: Radomes are used to cover the antenna’s exposed surfaces with a weatherproof enclosure, which protects the antenna and other integrated components from excessive amounts of ice, water, or other environmental particles. The use of a radome in stationary antennas can prevent the ice from de-tuning the antenna to the point where the impedance changes drastically, resulting in an impedance mismatch. As a result, the signal will reflect back to the transmitter, which will drive the system to higher power levels, causing over-heating and possibly, damages. In such cases, the use of radomes becomes an indispensable asset.

Satellite Radar Dish Antennas: Radomes are also used to prevent interception of signals by adversaries to decode or decrypt secret information traveling between satellite networks such as between satellite and nearby drones/UAVs or most commonly, satellite and ground terminals. They are used to prevent observers from observing the looking-direction of antennas in the ground, which in turn makes them more difficult to predict which satellites are in the field of view (FoV).

Maritime Communication: Radomes are used to protect dish antennas which track satellites in order to communicate with the ships located several miles away. They prevent other adversaries from understanding the direction of tracking and motion of antennas.

There are specialized manufacturers who design and develop radomes to support different types of applications such as for weather radar: airborne, maritime, and land, air traffic control (ATC), telemetry, and satellite communications applications. Click here to see a list of antenna radome manufacturers.

Example Radome. This is the protective covering for an antenna.

Air-Filled Radome - In this Case, the Radome is filled with air.

Radome used for mm-Wave Backhaul Applications. The Antenna and sometimes even the Tx/Rx modules are integrated into the radome.