Ku-Band Waveguide Rotary Joints for Satellite Communication Systems

Fast internet connections and mobile communication networks are not readily available everywhere. In places where transferring high amounts of data is required, however, the use of satellite communication systems frequently represents the preferable or the only possible option. In this context, in many cases, so-called VSAT systems (Very Small Aperture Terminals) are used which are operated on the Ku-band. These systems, which can be installed on all kinds of vehicle and can also be portable, make an exact positioning of the narrowly emitting antenna towards the corresponding satellite necessary. For this purpose, these systems contain rotary joints, which guarantee a low-loss and rotation angle independent transfer of the transmission and reception signals between the stationary transmitter and a moving antenna system.

Waveguide Rotary Joints

Applications in which both the transmission and reception signals are to be transferred via a single waveguide path require rotary joints usable on a relatively broadband basis, as these frequency ranges have to transmit both the downlink band (10.75 to 12.75 GHz) as well as the uplink band (13.75 to 14.50 GHz). SPINNER offers waveguide rotary joints of this kind in the waveguide size R120 / WR75 in different configurations (BN 635707, BN 635709, BN 635710).

In recent times, SPINNER has been in receipt of several enquiries in which the large bandwidth of the stated rotary joints was expendable, yet a reliable transfer of the transmitting signals was required at the lowest possible costs.

In response to these customer requirements, SPINNER is introducing two new single channel R120 / WR75 rotary joints which are designed in an L shape. BN 635725 represents the standard model in protection class IP40, while BN 635726 has an additional seal assembly. This means this model achieves protection class IP65 and is suitable for outdoor use. Both models are constructed in an intentionally simple chrome casing that is made from seawater-proof aluminium alloy.

Both rotary joints stand out thanks to their cost-optimised design that is made possible with an intelligent design and appropriately rationalised manufacturing. It goes without saying that no compromises have been made in the context of the quality features typical of SPINNER rotary joints (such as, for instance, the mechanical precision, the monolithic design, the abrasion proof laser engraving, and the well-known good high frequency parameters). As these are non-contact rotary joints, an exceptionally high lifespan is achieved which is to all intents and purposes only impinged upon by wear to the roller bearings. Through the widespread elimination of internal contact points, there is a very low insertion loss that is typically less than 0.1 dB, and an excellent cooling of the coupling system. Both are the basic requirements for a high level of corresponding durability which – like all other parameters – is naturally guaranteed in the full temperature range.

Low manufacturing tolerances for all of the individual parts in combination with precise assembly enable the achievement of high series stability and the high stability of all electrical parameters over the rotation angle at the same time.

The combination of superb high frequency technical attributes, mechanical precision and low costs makes these rotary joints the first choice for all Ku-band transmitting applications.