Waveguide Rotary Joint – For Better Communication

Rotary Joint

An important part of a radar antenna system is the rotary joint-it is used to connect two different parts of RF waveguide. The rotary joint must be capable of transmitting high, microwave power with a minimum loss.

The Rotary Joints can have the following styles of connection between waveguide port and rotational axis:

• U-style: Both waveguide ports at a right angle to the rotational axis.
• L-style: One waveguide port at a right angle and one in line.
• I-style: Both waveguide ports in line.

Advantages of Waveguide Rotary Joint are:

• High power maintaining capacity.
• Wide bandwidth.
• Different configurations.
• Availability of Multi-channel joints.

Types of Waveguide Rotary Joint

• Single channel
• Dual channel
• Multi-channel


• 360° Continuous rotation
• Straight and right-angle ports available
• Low insertion loss
• 1.5– 20 GHz wideband operation


• Mechanically scanned antennas
• Automatic test equipment (ATE)
• Axial ratio measurement

Description of Waveguide Rotary Joint

It is commonly used to scan any kind of antennas in radar and radmeter.

Input and Output ports are available in different positions like: io

• Straight to straight,
• Right angle to straight,
• Straight to right angle, and
• Right angle to right angle variations.
• An extended port available on the ends of the rim

Coupling is by means of flange to ensure good electrical and mechanical support, hence low radiation and internal reflection. The flange end of the unit is joined with the mounting disc, while the rotating side is free to move.