Due to the requirement of the customer to operate an antenna system in a high temperature environment, SPINNER had to take the challenge to design a rotary joint which was able to handle 1kW of average power at 10GHz at an environmental temperature of +60°C.

The power amplifying is normally part of the phased array antenna and is generated right behind the radiating element. Due to the high outside temperature of +60°C the power had to be generated in an air-conditioned shelter below the antenna. The power is then transmitted via a waveguide system up to the rotating antenna.

To be able to handle the massive data transfer requirement between the rotating antenna and the processing unit down in the shelter, the decision was made to use fibre optics. The data is transmitted between the rotor and stator via a 12 channel single mode fibre optic rotary joint (FORJ).

The stator fibres run through the core of the waveguide rotary joint and are exposed to very high temperatures.

The high average power of the waveguide rotary joint combined with the high environmental temperature of the system made it necessary to use high temperature fibers for the connection between the rotor and stator of the system inside the center of the of the waveguide power channel.

In spite of all challenges associated with this task, the rotary joint has a very low insertion loss and VSWR figures in the power channel. This special assembly combines traditional transmission with the latest state-of-the-art FORJ technology.