Spinner has developed a compact dual channel X/S-band rotary joint with encoder for a new coastal surveillance radar system that is being deployed along the Indian coastline. The antenna is 6.56 m long and 1.87 m tall and weighs approximately 1,200 kg.
Connected to two, separate, transceivers the radar system combines high-resolution capability for good weather conditions with long range visibility in the X-band and for bad weather conditions, for example high precipitation, it employs the S-band. With high gain and smaller than 0.4° beam widths in the X-band and smaller than 1.2° in the S-band the radar system can resolve and track small sea targets in all weathers.
To be able to achieve the superior system performance, very low insertion loss, VSWR and high isolation values for the rotary joint are necessary. For high availability of the system an easily accessible configuration of the angle encoder is also required. This was realized by a gearbox, which moves the angle encoder eccentric of the rotation axis. Therefore, a replacement is possible without much assembly and interaction with the total system.
