The European Space Agency (ESA) has developed a mesh reflector for shaped radio beams. This prototype 2.6-m diameter metal-mesh antenna reflector represents a big step forward for the European space sector: versions can be manufactured to reproduce any surface pattern that antenna designers require, something that was previously possible only with traditional solid antennas. China and the US have also been working hard on similar shaped mesh reflector technology. This type of antenna is needed so that sufficiently large antennas can be deployed in orbit, which would otherwise be too bulky to fit inside a launcher, while also meeting required performance levels.
ESA’s AMPER (Advanced techniques for mesh reflector with improved radiation pattern performance) project was developed with Large Space Structures GmbH in Germany as the prime contractor and TICRA in Denmark as a subcontractor. The AMPER project was supported via ESA’s Technology Development Element, with prototype testing carried out in ESA’s Hertz chamber at its ESTEC technical center in the Netherlands. As a next step the AMPER team plan to produce a deployable version, aimed at Earth observation as well as telecommunications uses.
Antenna reflectors for satellites are often surprisingly ‘lumpy’ looking. Their basic paraboloid convex shape is distorted with additional peaks and valleys. These serve to contour the resulting radio frequency beam, typically to boost signal gain over target countries and minimize it beyond their borders. This tailored surface shaping is traditionally done with traditional metal or carbon fibre reinforced plastic composite reflectors. The challenge was how to reproduce such shaping using a mesh reflector design. The obvious solution would have been a conventional tension truss double layer solution, with the mesh held together tautly on an alternating ‘push and ‘pull’ basis.
The design of the shaped mesh reflector is based on tension members supported by a peripheral truss structure which enables decoupling of the shaped surface and the structure. Therefore, the design can be implemented for any size of reflector, for any frequencies ranging from P-band to Ka-band. Furthermore, either deployable or fixed reflector technology can be realised. This 2.6-m ‘breadboard’ prototype proves the concept at C-band frequency, and the RF measurements have shown good correlation with radio-frequency and mechanical predictions.
This prototype reflector will be on display at next month’s virtual ESA Open Day at ESTEC.
