SPINNER

R84: A Challenge for Development & Design

R84: A Challenge for Development & Design

SPINNER

The products of the R84 family represent a new generation of broadband single channel waveguide rotary joints, which were especially developed for the field of SatCom and can offer outstanding RF values.

With the development of the rotary joint, the RF design follows well-known principles and designs of RF components. It tries to optimise geometries and fulfil the required performance data as best as possible by the skilful application of RF calculation software and a wealth of experience. This results in designs that cannot be produced in one piece due to technical production and economic necessities. A multi-part method of design results in a number of connection points. Joints are built taking into account production tolerances, which have a certain spread width of RF performance that needs to be constantly minimised.

By incorporating the tolerance analysis of components into the simulated RF model the most stable electrical layout can be determined and implemented from a large number of curves. Thanks to the consistent use of precise turned and milled parts made of solid material and the avoidance of welded metal structures, which are associated with high production tolerances, SPINNER rotary joints have already had a very uniform characteristic for years. Special adjustments during installation remain the exception.

Unlike with previous approaches, with the development of the single channel R84 family certain manufacturing methods, designs and dimensions were already compulsorily specified with the RF layout of components. A field strength analysis that can detect potential weak points in the design in advance, makes the problem-free optimum RF performance and highly integrated design possible later on. With its help, a reduced number of required components are produced on a few highly intelligent controlled turning and milling centres. As well as the CAE-CAD 3D file exchange formats already being applied between design and RF development, the 3D data is fed to the machine for production using the CAD-CAM software. The consistency of component information is thus guaranteed. However, it is only the company's own know-how in manufacturing that makes it possible to produce such complex components reliably and with a high cutting degree.

Furthermore, for the R84 family an innovative method for tuning the ball bearing is applied, which helps to reduce installation times and makes a backlash-free bearing possible. This results in the following advantages for the rotary joint:

  • Just a few high-precision parts are required to transmit RF signals
  • There is no need to prevent problems with contact to connection elements caused by aging thanks to the use of monolithic RF structures
  • High degree of match between simulated and produced geometry as well as simulated and measured electrical performance
  • No special adjustment measures

This results in the following advantages for our customers:

  • Superb values for insertion loss and VSWR
  • Very low electrical variation over rotation - WOW is possible among other things thanks to the minimisation of concentric run-out fluctuation of RF coupler structures
  • Reduced spread width of different joints' measurement graphs
  • Large reserves for specified values
  • High heat dissipation thanks to monolithic RF structures
  • Durable, robust and vibration-resistant design
  • Reliability

All the R84 series joints allow a pressurisation of 2 x 105 Pa (2 bar), are equipped with durable seals and guarantee a degree of protection of IP65 in accordance with DIN EN 60529. The joints are predominantly made of aluminium and are ideally suited to flying applications thanks to their low weight. Other features can be found in our‚ ‚Product Finder' datasheets on our website.

The advantages of the R84 family are being incorporated into other product series such as the R70 and R100 rotary joints.