Radar antenna

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The radar antenna is one of the most vulnerable parts of the radar system . The antenna is mostly used in time division multiplex operation in reconnaissance radar devices. During the broadcast time, the high-frequency energy is radiated into the free space. During the reception time, it then receives the energy reflected from the targets.

General

Radar antenna for the Airport Surveillance Radar . Below primary and above antenna of the secondary radar .
Radome under which the radar antenna is concealed
Radar system of the Kelheim barge at the Melk power plant , Austria (2019)

The radar antenna fulfills the following functions in the overall system of the radar system:

  • The antenna converts the high-frequency energy from the transmitter into electromagnetic fields and distributes the power in certain directions. This process is reversible for receiving the echo signals.
  • The antenna ensures the required antenna pattern and the required power distribution in the room. The antenna pattern has to be very narrow in the angle to ensure sufficient accuracy and resolution.
  • The antenna must update the received data from the targets quickly enough. In the case of a mechanical space scan, the antenna must rotate very quickly. This rapid rotation can cause a considerable mechanical problem because the antenna reflectors reach very large dimensions in certain frequency ranges.
  • The antenna must measure the current radiation angle with high accuracy.
  • The antenna construction must ensure these tasks under all weather conditions. For this reason, protective radomes ( English radar dome ) are often used, which ensure reasonably stable environmental conditions.

The performance of the radar system is represented in a mathematically simplified way, directly proportional to the product of the effective antenna size and the transmission power. An investment in the antenna always has a direct effect on the performance of the radar device. If these antenna requirements are taken into account, two basic forms of radar antenna are mainly used:

The radar antenna is usually changed as a complete assembly with the antenna turntable, also known as the turntable. This antenna turntable also contains other essential components of the radar device:

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