Abstract:
Knitted materials made of a microwire are widely used in space systems as reflecting surfaces
of transformable parabolic reflector antennas. To increase the reflecting properties and improve
the radio-technical characteristics of the antenna, the microwire is usually covered with a gold
layer of about 0.2 microns thick. However, according to the theoretical calculations and
experimental investigations, when a large antenna hits streams of stationary plasma engines of the
satellites, the dispersion (erosion) of the gold covering occurs. The erosion magnitude can reach
several microns. Since the covering thickness which defines the reflection factor of the radarreflecting
surface is about one-tenth of a micron, the erosivity of the specified streams can
significantly reduce the efficiency of the antenna. In this regard, an increase in the coating
thickness to at least 1 micron or even more is required. Since large antennas are knitted from a
tungsten microwire with 15 microns in diameter, it is necessary to estimate the effect of the gold
covering of 1 micron thick or more on the bending moment of such microwires, shape
recoverability after a bend, and permanent deformation after a plastic bending.
In this paper, the effect of the gold coating thickness on the bending diagram of a tungsten
microwire of 15 microns in diameter is theoretically considered. It has been revealed that the
coating of about 2 microns thick has essentially no effect on the bending diagram of the tungsten
microwire and, therefore, does not significantly affect the physical–mechanical properties of the
reflecting surface of antennas knitted from such a microwire.
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