What are RF Rotary Joints?

RF Rotary Joints are the electro-mechanical components used to transmit RF signals between stationary and movable parts of a system.

In some applications, a stationary RF line needs to be connected to moving components of a system, like that of an aviation radar, where the radar antenna is constantly rotating and is connected to a stationary ground system through a cable. Rotary Joints allow these types of connections with low losses and minimal variation in performance while they are rotating. These joints are usually available in three main geometrical configurations called I Type, L Type and U Type. These define the shape of the overall rotary joint.

RF Rotary Joints can broadly be divided into three types:

Coaxial Rotary Joints: These rotary joints have coaxial input and output terminals. One of the connectors will rotate while the other one will be fixed. The power handling capacity and frequency range of coaxial rotary joints are restricted by the power/frequency limits of the connectors. Click here to see coaxial rotary joints from the leading manufacturers.

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Waveguide Rotary Joints: These rotary joints have a waveguide interface at the input and output terminals. One of the terminals rotates while the other one is fixed. The operating frequency of this type of rotary joint is limited by the waveguide size. Click here to see waveguide rotary joints from the leading manufacturers.

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Waveguide to Coaxial Rotary Joint: These rotary joints have a waveguide interface at one terminal and coaxial interface at the other terminal. In this case, the operating frequency is limited by the waveguide size and the type of connector used whereas the power is limited by the coaxial part. Click here to see waveguide to coaxial rotary joints.

Image Source: Link Microtek